This circuit will allow you to control any electrical gadget from any part of the world through your cellphone remotely, that too without spending a penny for the individual commands.
Circuit Concept
Whether it’s you vehicle, your basement door, your mansion gate or simply the air conditioner of your house, everything can now be switched by just a flick of your cell phone button.
And yes, it’s completely fool proof, meaning no false triggering is possible through any other cell phone signals, it works only through the owners cell phone commands.
The explained circuit must be employed strictly for operating only the following specified equipment:
All domestic electrical appliances like, lights, fans, motors, TV sets, refrigerators, Air conditioners, washing machine, porch lights, garage door, house gate, basement gate or entrance, car ignition, car doors, water heater etc.
The concept has been already discussed in one of my previous articles – How to make a GSM car security system, and the going about is unbelievably simple.
However, the above article deals with a system that involves DC control features and therefore is not suited for controlling AC appliances.
The unit discussed here is a universal device and can be used for operating all types of electrical gadgets from any part of the globe, just by making a single blank call to the systems number.
The system will faithfully respond to every call made from your cell phone and will alternately switch the connected load ON and OFF as per your instructions.
The concept is impeccable, as it has been tested by me thoroughly since last three years with flying results.
Basically the unit employs a very fundamental principle of converting the ringtone of a cell phone into a command output for operating a relay.
This cell phone acts as a modem and is permanently attached with the internal control circuit of the unit. The modem cell phone is initially made ready by putting a SIM card inside it and by configuring the essential assigned numbers into its phone directory.
These assigned numbers are the only numbers to which this modem responds. Therefore you would want to assign only those numbers through which you may like to make a call to the “system”.
For safety reasons more than one number is assigned to the modem so that in case one of your cell phones is out of order or has low battery, you always have the option of using the other cell phone for triggering the system.
The biggest advantage of the GSM cellphone remote control circuit is that, any cheap NOKIA cell phone can be used here as the modem and therefore there’s no fear of the modem becoming obsolete.A simple yet effective cell phone remote control switch details has been discussed here with complete schematics and step by step tutorial.
UPDATE:
Looking for an advanced solution? Read more below:
Advanced Microprocessor Based GSM Remote Controller
If you have sufficient prior knowledge of electronics, you should be making this complete unit within a days time. Let's begin the discussion. Basic Concept The idea here is to use an ordinary NOKIA 1280 cell phone as the modem attached permanently with a switching circuit. This entire unit now becomes the receiver unit.
The modem cell phone NOKIA1280 is assigned with desired numbers, for example the owners cell number and a few other numbers of the owners family members.
When the modem cell phone is called through these assigned numbers, the modem ring tone becomes active and this ring tone is applied to the control circuit and is processed for operating a relay and the connected load.
Since the modem cell phone needs to be attached permanently inside the switching unit, it needs to be charged at regular intervals so that it remains functional all the time.
For this, a separate cell phone charger module has also been incorporated along with the main circuit which keeps the modem cell phone battery always up to date and fully charged.
It is quite obvious that the attached cell phone modem will need a SIM card, which will need to be maintained as we do for normals cell phone operations.
Let's learn the building process. You will have first get or procure the following materials or parts for making this unit. I would suggest not to make the Printed board initially, it would better to first test the working over a general board and if thing goes then you would want to transfer it over a well designed P-C-B.
Bill of Materials
All resistors are 1/4w 5% CFR unless otherwise stated.
R1 = 22k
R2 = 220 OHMS
R3,R11,R12 = 100K R13 = 100 Ohms
R4,R6,R7,R9 = 4.7K
R5 = 1K,
R8, R10 = 2.2M
C1,C4,C5 = 0.22uF DISC TYPE
C2,C3 = 100uF/25V
T1,T2,T4,T5 = BC 547B
T3 = BC557 B
ALL DIODES = 1N4148 IC1 = 4093
RL1, RL2 = RELAY 12V/300 OHMS SPDT
JACK = 3.5mm AUDIO JACK
CELL PHONE MODEM = NOKIA 1280
Circuit Diagram
Understanding the Schematic Diagram
The above schematic of the proposed cellphone controlled remote circuit is rather very easy to understand. It may be divided into two main stages, the lower stage consisting of the transistors is a simple audio amplifier, the upper stage consisting of IC is the flip flop triggering stage.
When a signal is present at the 3.5mm jack, which might be the input ring-tone from the cell phone modem., T1, T2 amplifier to some greater level, which is further amplifier by T3, T4 to a level is becomes sufficient for triggering the relay RL1. RL1 instantly connects the supply to the input of the flip flop at C5, via its N/O contacts.
Note that RL1 will remain switched ON as long as the ring tone is present and will switch OFF the moment the ring tone or the signal over the 3.5mm jack is canceled. C3 makes sure that the relay does not get rattled by any insignificant signals or RFs.
L1 has been installed also for the same reason, that is for eliminating unwanted signals and making sure that T3, T4responds only to valid ring-tones.
L1 is a buzzer coil, as used in piezo electric buzzers, or may be hand made by winding 1000 turns of 36SWG super enameled wire over a small ferrite core, size and shape does not matter. Image of L1, inside a buzzer
The period for which RL1 remains switched ON will have no consequence on the flip flop operation, the flip flop will switch ON and OFF in response to every subsequent missed call made from the owners cell phone.
The section comprising the IC 7805 is battery charger section, which needs to be connected to the battery charger input of the cell phone.
The charger will keep the cell phone battery always charged so that it remains functional all the time. The above circuit has been thoroughly tested and confirmed by me, so if you make everything as shown in the above diagram, it should start working immediately.
How to Assign Numbers Inside the MODEM CELL PHONE It's very easy. Just follow the following steps. Save the names and the numbers which are important and through which you want the above unit to be operated.
Next select a particular name-->--press scroll right-->--"contact details" will be displayed-->-- press options-->--scroll down-->-- select "assign tone"-->--select a ring tone which has a sustained, non-breaking tune-->-- do OK. Repeat this for all the desired numbers. Now go to settings, go to tone settings and select "empty", press OK.
That means now you have switched OFF the default ringtone and no ringtone will be audible for any numbers other than the above assigned ones.
So you can be rest assured that the system will not respond to wrong numbers or any unknown numbers. It will respond to only the calls made from the assigned numbers.
How to Power the Unit
The circuit needs to be powered through a DC12V/500mA or 1 Amp SMPS adapter.
The load may be any electrical appliance like lights, fans, AC, fridge or anything that you may like to switch using this system.
Video Clip showing the circuit functioning of the prototype
WARNING AND DISCLAIMER – THE PROPOSED DEVICE MUST BE USED FOR OPERATING ONLY THE COMMON HOUSEHOLD ELECTRICAL SYSTEMS AND PARAMETERS. THE PROPOSED CELL PHONE OPERATED SWITCH MUST NEVER BE USED FOR ANY OTHER INTENTIONS OR PURPOSE WHATSOEVER, AND THE AUTHOR TAKES NO RESPONSIBILITY FOR ANY LOSSES THAT MIGHT OCCUR IN CASE THE UNIT IS USED FOR OPERATING ANYTHING ELSE OTHER THAN WHAT'S BEEN SPECIFIED IN THE ABOVE ARTICLE.
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Felix jesmine says
Please what IC did u use in the circuit and the voltage of the relay
Swag says
IC is 4093, relay coil voltage will be as per the supply voltage, preferably 12V
Mathew Mani says
Sir
The nokia phone with me is Model no. 101 Type RM769.
Is it suitable ?
Is it possible to on off more than one relay?
Swag says
Mathew, I think it should work, however only a practical test can confirm this, yes you can apply more relays in parallel by appropriately upgrading the driver transistor
Ankitesh Singh says
Sir,
I want to control 5-6 different LEDs and motors via phone.
I mean one phone should e connected to the motors or LEDs and via other phone with help of any app I can switch to those LEDs. with any limit.
please heelp me sir..
Swag says
Hi ankitesh,
you can try the following concept
https://homemade-circuits.com/dtmf-based-fm-remote-control-circuit/
in the first circuit remove the 5089 and the key pads instead feed the transmitter from your mobile earphone jack, and with DTMF app activated
Unknown says
The first relay goes on clicking and the secomd relay works only when the audio.jack is touched. And does this circuit only works with nokia phones. Please explain
Davis Kakumba says
Helo SwAGATAM the circuit works great with battery powered but when i use smps adapter 12v 1A it behave crazy and relay 2 switches on the connected load have failed to triubleshoot this i tried puting resistor on + of smps but failed please help me because i want to use that adapter than battery
Swagatam says
Thanks Davis, if your relay is making noise, you can add a capacitor parallel with the relay coil
you can add more relays in parallel, but make sure the transistor is upgraded appropriately to handle the relay coil current
Davis Kakumba says
Helo SWAGATAM thanks for that great circuit. I made it and works fine using battery but when i change and power it with 1A 12V smps adapter Relay2 activated and switch on load and makes even sound. Help me coz i want to use smps adapter rather than battery. Also help me how to connect other relay to connect multiple appliances. Thanks u great
Swagatam says
Thanks Davis, if your relay is making noise, you can add a capacitor parallel with the relay coil
you can add more relays in parallel, but make sure the transistor is upgraded appropriately to handle the relay coil current
s.ahmed@outlook.in says
Hello Sir,
This is a great Circuit, I want only connection during phone ring, every time. Pls help, i am very exited,
Thanking you In advance !!
saji.R says
Hello Sir,
can you advise me whether i can use SFM-27D electronics buzzer coil as L1?
Swagatam says
Hello Saji, if it is same in appearance to the one shown in the image then it would work
swapnil dhobale says
sir can u plz give me a simple ckt diagram bcoz i am beginer and also i want one pick of ur project that will help to buy component sir i hope u will help me
Swagatam says
swapnil, you can try the following circuit
https://homemade-circuits.com/2012/01/how-to-make-simple-timer-circuit-using.html
India is my country says
Sir i want to use such a circuit for 3 phase 5HP motor. Can i get circuit diagram and details video please..!
Swagatam says
use 3 parallel relays for REL2 and connect the motor across the 3 contacts of these relays,
Sam Devil says
how did rl1 get on its one pole is connected to vcc and other to t4
Vishal Sherathiya says
Hello sir,
I have build the bottom part of the circuit.
When I touch C2, the relay and LED turns on. So, as your suggestion in other comment I connected 0.1uF capacitor in parallel with L1. Now there is no more problems in that.
But in either case, if I have 0.1uF capacitor in parallel to L1 or not, I never get my relay or LED turn on when phone rings. What should I check?
I have used 390uH coil in place of L1.
Swagatam says
Hello Vishal, though very strange, it seems the audio signal is not powerful enough to drive the relay….you can connect an LED parallel with the relay coil with a series resistor and check if this LED lights up or not…this will prove whether the signal is weak or the relay is incompatible.
If possible I'll try to update another easier and a foolproof design soon.
Vishal Sherathiya says
Thank you for reply sir,
As shown in the above circuit, I connected the LED. But the above LED is not lighting up.
When calling If I check voltage on Audio Pin, I get 0 Volts.
Swagatam says
Vishal, keep your meter in the 200mV or 400mV range whatever may be the range available in your meter but make sure your meter is in the AC range….and now measure the voltage of the ringtone without connecting it with the circuit….
Gajanan says
hi. I have build circuit. but when iam testing lower amplifier circuit the RL1 sometimes responds correctly to calls. sometimes RL1 switches on when dc power is switched on. what is the problem?
Swagatam says
if RL1 switches ON momentarily during power switch ON then that's not a problem, it could be a sudden transient, you can try adding a 0.22uF capacitor parallel with L1 to rectify this…
but RL1 must respond always to each and every call…
Gajanan says
hi. I made my lower circuit to work. but I want to know the exact operation of lower circuit. and also how can I test upper circuit before connecting it to lower circuit.Thanks in advance.
Swagatam says
the upper circuit details are given in the following article, read the 4093 explanation, you can check it as explained
https://homemade-circuits.com/2011/12/build-these-simple-flip-flop-circuits.html
the lower circuit is just a simple transistor amplifier…with each transistor amplifying the previous transistor signal to a greater level
Gajanan palankar says
When i give call to phone, relay ticks and led glows both relay and led is on until i dont disconnect the call. Is that ok? Or correct operation? But if i see your video in that the green led is on for little time but in my case led remain on till call is connected.
Swagatam says
It is correct, in my video I might have cancelled the call or I might have used a "one beep" ringtone in the modem, it was created a long time ago I don't remember now..
Sanjay doifode says
How I can get total circuit except mobile
Nilotpal Mukherjee says
Hi…. can i use 220nf instead of 0.22uf and diodes like 1n4007 ????
Swagatam says
0.22uF and 220nF are one and the same…so it's fine. 1N4007 will also work
Unknown says
0.22uf cant find… may use 220nf ???
Mohit Agarwala says
Hello sir, I am working on this project of yours and i need some help. Is it necessary to use nokia 1280 or any other set can do ??? please help …regards Mohit
Swagatam says
Hello Mohit, any phone which has an "assign tone" feature will work for this project.
sanjoy says
Dear Swagatam, As I could not debug the problem in the the vibration detection based circuit I decided to go for this one. I assembled the circuit(the lower part or the amplifier only) on bread board. When powering on the the RL1 and the associated LED is getting activated by default(which should not happen if the circuit works properly). Well then I went through the comments section and found once you said to put a .1 mfd cap. across the buzzer coil legs. I did that. Now the RL1 and associated LED is not turning on by default but it is not responding to ringtones neither. Surprisingly the if the A or B and the ground connection of the earphone shorted the led and the RL1 turns on and remains turned on as long as the two points of the earphone remains shorted. I know from this behavior you will be able to suggest proper correction to be made to the circuitto get it worked. Please help. Wish you happy and prosperous 2016 ahead.
Swagatam says
Dear Sanjoy,
I am sorry this problem is not familiar to me, because I never encountered such an issue while making the design, I have already made hundreds of these circuits and none gave me the mentioned issue, so I am clueless about it.
first of all the coil L1 and the associated capacitor have no direct relation with the circuit triggering, the circuit should work even without thees components, these were introduced to prevent accidental and false triggering each time the charging was imitated internally which strangely created unwanted RFs and triggered the relay spuriously, so by introducing L1 and the parallel capacitor completely eliminated this problem, so this cannot be relevant in your case.
The problem could be somewhere else in your connections, or may be the cell phone is not generating sufficient input voltage, make sure it's minimum 100mV from the cellphone headphone, otherwise the circuit might not respond.
Wish you too a very Happy and a prosporous 2016 🙂
Setute Hotor says
Sir,
I have a weird problem, the air conditioning unit in the office draws too much current when switched on. The machine can only work for a few minutes before the power feed trips. Can u suggest a circuit that can solve the problem
Swagatam says
Setute, the problem could be specific, it won't be possible to judge it without a practical check up…it might need a repair from an expert AC technician..
Swagatam says
,
Unknown says
Dear Sir,
I am interested in this circuit.I want to know limit of the motor rating.like 0.5 to 100 hp motor operated with this circuit. total no of mobile no from which this circuit operated.
Swagatam says
motor rating will depend on the relay contact rating….both must be rated equivalently.
you can operate it with any number of mobile phones, by assigning the numbers….. as per the given instructions in the article
abdulrasheed abdulganiyu says
please could you send me the calculative analysis of the circuit
Devashish Paighan says
devashish
ijust want to know how to start 3 phase induction motor using the same assembly
Swagatam says
use three relays in place of the RL2 and wire the 3 phases through their contacts with the motor
Chandu Reddy says
I am Chandra from Nellore AP Sir first circuit (I mean amplifier circuit) working properly. give misscall glowing LED and RL1 is activate good, but second circuit flip flop is not functioning. it is not work properly give the miscall LED only flash and RL2 is also active and relese automatically within seconds. I also tryed second circuit of flip flop but in vain (https://homemade-circuits.com/2011/12/build-these-simple-flip-flop-circuits.html). I am living in remote area. so I want to know what is the problem of the circuit (sir I tried above 15 flip flop circuits but no result) please help me sir my mail ID samscruti@gmail.com please reply me. sir I did ferfectly. but some mistake is the circuit or values of resisters please help me
Swagatam says
I have made dozens of the above circuit model, all have worked perfectly
anyway…you can try the IC1 section of the first circuit that's shown in the following link:
https://homemade-circuits.com/2011/12/make-simple-electronic-clap-switch.html
include C3, R5 at its pin14 and exclude everything that's associated with T2 and T1 section….
now connect your RL1 output with pin14 of the IC.
Ramkesh Meena says
Sir I want to extend this concept to operate on 3 phase motor starter (10HP motor)
I am doing farming…due to loadshedding it is very hard to start motor at night time by visiting physically…..
Swagatam says
Thanks Ramkesh, I will definitely design it and post it in my website…however it might take a little time to get it posted due to many pending assignments in the line…
Ramkesh Meena says
Dear Swagatam,
This is with reference to the comment of Mr. Raj Mukherji, January 16, 2013. He explained it very well. In addition, farmer suffered from infrequent power cut (6 hrs ower supply in aprox. 10 irregular blocks) so it is very irritating for a person.
I want to apply this type of circuit for three phase induction motor in my village and it will be make for my village also. I humbly request you to develop the circuit for the walfare of our poor villagers. They are not able to purchase it from market.
I will be greatful to you.
chip_trauma says
Hi! Thank you very much for your work, greatly appreciated. Could you please give some more information on L1. I'm now using a 1 µH coil. My relais isn't switching though. Could this be the problem? It would be very helpful to have a specified value for this coil, so if you could, please.
Greetings
Swagatam says
Hi, the coil must have a value of around 40mH…….1uH is too small, it's like short circuiting the base/positive of the transistor, which will never allow the BC557 to conduct, so it won't work….use a 40mH coil or a buzzer coil as shown in one of the article images.
Evans Kofi says
Hi sir,
Great work done, God bless you.
I am now building the circuit, although I have not finished it yet, I forsee it beneficial.
I have followed carefully all the comments ant replies you and it gives me enlightenment.
Someone asked about the how to receive feed back as to whether the output( pump on farm) is work or not. Is there any additional circuit to that. I really need it.
Secondly, it difficult getting the ic , is there any alternative? I have TDA 16846 will it improvise it?
Thank you.
Swagatam says
Thank you Evans,
for getting a feedback response you can try the following concept:
https://homemade-circuits.com/2012/04/make-this-cell-phone-call-alert.html
which IC are you referring to? but anyway, only the specified ICs will work for the above explained circuit.
Sagar Aher says
Sir I want to extend this concept to operate on 3 phase motor starter….
I am doing grapes farming…due to loadshedding it is very hard to start motor at night time by visiting physically….. Please help sir….
Swagatam says
Sagar, you can use three parallel connected relays for RL2 and integrate the contacts with the three phases of the motor supply
sangit says
Dear Swagatam, thank u for this innovative circuit. Just completed the circuit on a breadboard and in the first attempt it is working perfectly. I have used stage2 circuit from one of ur previous projects (ir remote switch using ic4017) and lenovo p780 instead of nokia 1280. Your circuits are fullproof!!!!! Thanks again.
Swagatam says
That's great Sangit, thanks for updating the results here…appreciate your efforts.
Shuva Bhattacharya says
sir how to use this circuit to control 4 wire, 1.3kg torque ,12v stepper motor.?
Swagatam says
sorry I do not have any idea about it…
Bhawana says
Thank You Sir!!! 🙂 🙂
Swagatam says
you are welcome:)
Bhawana says
Sir
I have some doubts,which are as follows:
How does L1 eliminate unwanted signals? Is there any tuned ckt. formation? If yes, what frequency is it tuned at?
Is C2 acting as coupling capacitor or is it forming a tuned circuit with L1?
Similarly, how does C3 prevent RF interference? Am I right if I say that C3 offers very low impedance at RF, so voltage across base-emitter junction of T4 is insufficient to drive it?
Why is it required to use PNP transistor for T3 while rest others are NPN?
At what frequency is the whole audio amplifier stage tuned to? What is the frequency of the ringtone?
I would be grateful for a prompt response.
Swagatam says
Bhawana, L1 here behaves like a choke, it grounds weak signals and saturates only under strong signals from ringtone. C2 is a blocking coupling capacitor.
C3 is positioned as a filter capacitor, cleans ripple.
PNP in the position of T3 becomes more appropriate for creating a high gain response, similarly the remaining must be NPNs
the circuit is not tuned it'll respond to any audio input above 100mV.
rajeevkumarverma41 says
Dear sir
please send me your mobile number rajeevkumarverma41@gmail.com
Bhawana says
Sir there is another question dat is hitting my mind. I would be grateful i u could answer it.
The mobile phones generally have Li-ion battery which are rated at 3.7V . So will it be feasible and correct to charge the battery with 5 V.
Thanks and regards…
Swagatam says
Bhawana, all cell phones have their own built-in voltage protection circuitry and will never allow anything undesired to the battery. Moreover the 7805 series resistor makes sure that the current is appropriately reduced for safe charging.
The 3.7 Li-ion cell will require 4.2V to get fully charged.
shadab karnachi says
dear swagatam,
i constructed this circuit on breadboard, i even got the buzzer coil very easily and i assembled this circuit, the last problem was that of powering the circuit, I have neither 12v smps nor any battery. But somehow i managed to get a lead-acid 12v 7ah battery. I powered it using this battery. The relay and the leds were "on" as soon as i powered it. But according to you this should not happen, right?
i could not understand the problem.
later I found that t4 was draining current to emitter and switched relay1 and led without base connection of the transistor.strange? Then i took all the transistor from the circuit and then I tested a basic circuit with each of them (excluding bc557) i.e I connected an led to its collector and then 1 k resistor to the other pin of led and connected the same battery i.e positive to other pin of resistor and negative to transistor's emitter. and without a single connection to the base the transistor, the led was "on", and all the transistors reacted the same. I am not getting the problem, but i those transistor are newly bought and working in other circuit.
please please reply soon,
i am in hurry
thanks,
regards
shadab
Swagatam says
Dear Shadab,
It clearly shows that all your transistors are faulty, if they are new it doesn't mean that they cannot be faulty…procure good quality transistors and make it once again, preferably buy original philips make transistors.
Or, if the transistors are OK it means you have not put them correctly, either ways the fault is in your circuit not in the above design.
Swagatam says
….you say that the transistors are behaving strangely, conducting even without the base connected, then how can the same transistor work correctly in other circuits????
shadab karnachi says
dear swagatam,
I forgot to tell another thing i observed. The statement i gave " working in other circuit" was true, i.e when i connect the transistor to other circuit of 9 volts and below it works completely ok, but when I power it with 12 volts battery or a 12 volts 1000 ma adapter to any circuit, it starts to behave like that.
thanks,
regards
Swagatam says
dear Shadab, BJTs are not supposed to work in that way, so there's something wrong with your components…replace them with new ones, from a different shop.
Swagatam says
..
shadab karnachi says
Dear Swagatam,
Suppose if we have fixed this circuit with a normal cfl bulb as load,and we are out somewhere. Then how to verify that the bulb is specifically on or off ?
thanks,
regards
Swagatam says
Dear Shadab, this feature is not present in the above design….may be "call back" function will need to be included for getting the required revert message.
Bhawana says
Sir, in order to include the message facility can we add another cellphone circuitry so that the on or off state of the load can be determined? Can this be done by a similar methodology or some decoders and dtmf technique need to be used for it?
Swagatam says
Bhawana, a text messaging facility may not be possible in this simple design, because sending a text message each time a call is made could be very difficult to implement.
Sending a revert missed call is possible though, but this modification will require the modem cell phone to be opened and two wires joined with its "call button"
Bhawana says
Sir i read your projects…and find them really helpful for students like me…
Thanks a lot for finding time to share your knowledge with others.
Could you please explain why the circuit works well only with nokia 1280? why not with others? What actually in the circuit differentiates between nokia 1280 and other cell phones??
Swagatam says
Thank you Bhawana!
The NOKIA 1280 has the "assign tone" feature which enables the unit to become foolproof with its operations, with this feature the unit won't respond to wrong numbers…. any cellphone with an "assign tone" facility will work as good.
Bhawana says
Thank you sir for the prompt response….
Sir i'll be grateful if u could explain how can this project be further extended in order to make it a big one. Can any more features be added?
Swagatam says
You can specify the features, if possible I'll try to include them.
Bhawana says
Sir u said that the above circuit is only for dc appliances…but why would it not work with AC appliances? RL2 contacts will still cause making or breaking of the circuit containing the load…so the ckt. should work fine with AC loads too. isn't it?
Swagatam says
Hi Bhawana, the DC operation was probably meant for the car GSM security system, the above circuit can be definitely used for controlling any electrical appliance.
Bhawana says
Thank u sir 🙂
Sasa Hadia says
Dear swagatam
This circuit is very sensitive that drives the relay during mobile charging.
It is also sensitive that drives the relay when you touch the input wire of C1 .
Can you please show me how can I reduce the sensitivity of the circuit to drive the relay during the ring tone only??
Thank you
Swagatam says
Dear Sasa,
Did you connect the L1 as indicated in the diagram….also please include a 0.1uF capacitor in parallel to L1…this network will make the circuit stable and unresponsive to spurious signals except the ringtone…
Shubham Nagpure says
sir i have made this circuit on breadboard but it is not respond correctly…………..RL2 remains on What is the reason sir……….?????????
Swagatam says
Shubham., first make sure RL1 responds correctly to the repeated missed calls…initially keep the upper stage disconnected from RL1.
If RL1 works correctly then proceed with the upper RL2 stage.
gs sidhu says
Sir plz give me the pcb layout of this circuit that is very important for me plz plz sir….nd sorry for my bad english
Swagatam says
sorry GS I lost the PCB layout film, so i don't have it now, you can take the schematic to any PCB designer and get the design made from them easily.
gs sidhu says
When i m connect the supply the relay one is automatically open i cant find problem plz help me
Swagatam says
did you call the modem phone….RL1 will stay activated only as long as the call is connected.
Ripon Dhali says
tell me which parts are not shown to the diagramme
Swagatam says
the circuit is perfect in every way, what is happening with your circuit? is RL1 activating when the modem is called??
Ripon Dhali says
i make this circut …but it is not working …..what can i do? plz help me
Murali Sanu says
Thanks for sharing the brilliant idea and circuit,sir.
*Are these 3.5 mm headphone pins available at the stores?
I feel it difficult to peel off the outer sheath of my headphone jack to take the pin out.
*What is the inductance of the buzzer coil used?Could it be replaced by one of the coils of a miniature driver transformer?
*Why T3 is a pnp transistor..?
I'am a beginner..
Regards
-Pranav
Swagatam says
Thank you Pranav,
Yes 3.5mm jacks are available as spare with an unscrewable plastic cover.
But this circuit is not for a beginner, you will have to first learn all the basics of electronics, do plenty of practicals with simple circuits and then attempt the the above project.
Murali Sanu says
hello sir .i like your project.. its a wonderfull. i need your big gift.
please send me this project FULL SCHEMATIC
MY G-MAIL–muralisanu97@gmail.com
Murali Sanu says
hai sir plz send me this project full schematic
muralisanu97@gmail.com
Beta says
sir, how can i connect relay 1 and relay 2 ….need more
Beta says
sir you give me the spec of IC4903
AJAY DUDI says
Dear Swagatam,
Can You Send this pre packed gadget, i will pay for it
Swagatam says
Dear Ajay, presently I am not manufacturing this unit so I am sorry I wouldn't be able to send it to you.
Asifur Rahman says
Sir
Can we use a camera mobile phone with 3g support to receive a video call from the user after a alert call been made ?
Swagatam says
I don't think it would be possible using a simple technology as above.
Deepak Soni says
Sir my circuit is not working….i have made ur previous project in which the circuit is on for only a short period till the phone rings i.e half part of dis circuit…. Without relay it is working properly bt when i connect relay it can not switch the relay….
I cant understand y it is happening so….
Plz help me…
My email id is rohitraj0000@gmail.com
Swagatam says
Deepak, you should make and test the upper flip flop circuit separately for confirming its operations. Once it's confirmed you may proceed to integrate it with the lower section. You may refer the second circuit from the following link for a detailed info regarding the flip flop circuit design:
https://homemade-circuits.com/2011/12/build-these-simple-flip-flop-circuits.html
Abdelrhman Hany says
you mean that there are 3 dc adapters or 1 only gives the 3 rails
Swagatam says
all (+) to be made common and joined with the (+) of the power supply, same for the "earth" rails.
Abdelrhman Hany says
how the +ve sign is a dc supply connected from only one side
Abdelrhman Hany says
how the +ve sign is a dc supply connected from only one side
Swagatam says
I did not understand your question…
Abdelrhman Hany says
I mean why the dc supply has only one branch ( +ve only )
and not 2 branches +ve and -ve )
Swagatam says
The lines with the earth symbols must be all connected with the negative of the power supply.
Abdelrhman Hany says
another question mr Swagatam did you mean that i'll connect the circuit with ac voltage source
Abdelrhman Hany says
i mean is the main Ac input is a connection between the circuit and the ac current from the wall
Swagatam says
(+) will go to +12V and the earth symbol to the -12V of a 12V DC adapter output terminals…..AC mains may be used for operating the load across RL2 contacts..
Joji says
hi ,
excellent article and concept..
i have a pumpset arounf 1/2 a kilometer away from my house,which pumps in water from the river.can the pump motor be toggled using this circuit,it is an 5 hp motor.if not can u suggest a method for doing so..i mean the changes to be incorporated for this functionality
Swagatam says
hi, thanks, yes you can use the above circuit for this application, just upgrade RL2 for handling higher current, you can replace it with a 30amp relay.
edds says
hello sir, am trying to simulate the above circuit to operate a dc 12v motor using national instruments and i have encountered some problems, firstly the l1 buzzer is not available, what other specifications would i use?secondly can i use a switch in place of the relays? third what is a suitable replacement of the 7805 ic for the charging circuit?
Swagatam says
hello edd, use a 40mH coil for L1,
relays are transistor/voltage driven components how can switches be replaced with them?
7805 can be replaced by any standard/suitable 5V regulator circuit or IC
Anonymous says
What may be the over all cost for this system?
Tsigabu Yemane says
Sir can't we replace the 4093 by 4011?
and my second question is; is it possible to see the output (result) by using only "the upper circuit"
vijay agrawal says
sir i am vijay and i want ask you
that, sir please give me pcb layout because i am not under standing its power supply
JustEasy says
Regrettably dear friend but this project is not only unsafe but also dangerous if not used by normal people brains.
Imagine if a person called us your number by mistake, he will have access to pasijen that you have built to be used only for yourself.
This is a project for beginners in electronics.
To have self control you control what you bu
dr vivek says
from dr vivek,
I needed a circuit to operate street lights of my farmhouse (60wTT X 3 bulbs) when I reach the gate guiding me to the door. If I purchase the circuir from you could you suggest me additional modifications. However I have to depend on an electronics technician based on your diagram plz help me.
Swagatam says
Dr Vivek, what modifications do you want to make in the system?? Please specify them.
Anonymous says
Dear Swagatam,
Thank you for posting this project. My 14 yr old son has started taking lot of interest in the circuit assembly due to some of the stuff posted here.
We assembled the circuit as per the diagram but on the power-on stage, both the relays are switching on (both the LEDs are glowing). Can you suggest any specific checks to rectify the same? Have I connected N/C OR N/O wrongly?
Can you pls confirm the pin diagram for KT 603?
Also, would the circuit work if another basic model of Nokia is used instead of 1280?
Pls let me know the contact details, to purchase some of the other kits? Regards.
Swagatam says
Disconnect RL1 link with the upper circuit and check the lower stage separately first.
RL1 will only operate momentarily on power switch ON, the LED connected parallel to RL1 coil will illuminate only for a second and then switch OFF, this might happen or might not happen….but under any case RL1 will not switch ON permanently when powered initially.
RL1 will switch ON only in response to a ringtone and will hold only until the ringtone is not cutoff, once the ringtone from the phone is disconnected, RL1 will instantly deactivate.
First confirm this then you can proceed with the upper circuit.
Swagatam says
…presently I am not selling any kits so would be unable to provide them to you!
Regards.
Anonymous says
Thanks for your revert. Pls let me know if L1 has to be of any particular specification?
Swagatam says
I have shown the example image of L1 inside the buzzer, it's exactly what would suit, alternatively any 40mH coil would work
jirah888 says
hello sir, i have a question. what is the voltan for the supply ?
Anonymous says
Hi Sir
I can not find R4,R6,R7,R9 = 4.7K , C1,C4,C5 = 0.22uF , R13 = 100 Ohms in the market. Can I use any others.
plz help…………………………….
Anonymous says
can i use any unit of phone for the circuit ????
Anonymous says
can i use any unit of phone ?????
Clied Aplaca says
sir can u help me i am building a project that control appliances, using call and text can u give me advice what will i do or can u give me schematic sir, that would be a big help sir! plz help!
Swagatam says
Hi Clied,
For text message control you will have to employ a GSM module, I don't have much idea about them, so you might have to take the help from some other source.
Clied Aplaca says
hi! sir can u advice me, sir i have a project in my school that can control all appliances in the house using call and text can u give me any advice or a schematic plz i need help sir!
Anonymous says
good work Bro, i am going to start this project pls help if any thing goes wrong…
Anonymous says
Dear Swagatam,
Your web site is amazing! I'm planning to just install an inductance to replace L1 as it would be easier for me. Could you please suggest an inductor that would be suitable?
Thanks in advance,
Pete
Swagatam says
Dear Pete,
Recently I got the oppurtunity to confirm its value, it's around 40mH….
Anonymous says
sir, what is the value of inductance L1
Anonymous says
Hi Sir Swagatam,
Can i control atleast 5 flourescent lights @ 20watts each with this circuit simultaneously?
Thanks.
Swagatam says
the relay contact rating determines the load handling capacity of the circuit, so it can be rated accordingly and used for handling any desired load or wattage.
Sunil Kumar says
i want to buy this circuit
muhammedalisageer tharammal says
Hi….
This Circuit Work On 10 Hp Delta Star Starter?????
And Mobile Charger Automatic Cutoff Mode Or Not???
Full Time Charging Battery Is Damaged….
Anonymous says
Hi Sir,
Does the position of LED and its resistor in the flip flop circuit correct?
from pos. supply to LED then to its resistor? Does it matter Sir? Thanks!
Swagatam says
The resistor must be in series with the LED that's only important, it doesn't mater on which side it's connected.
peter says
sir,
can we control independent circuits with this system ?
is the pin 11 of IC1 is open?
peter says
sir,
can we control independent circuits with this system ?
is the pin 11 of IC1 is open?
tet bernal says
Sir, what can we add to the device if we want the device itself to give us signal when it is time to turn it off? thankyou!
Swagatam says
you will have to add a "call back" feature in the circuit, which would make the circuit very complex.
Anonymous says
Hello Swagatam,
How can I get the ASSEMBLED AND TESTED CIRCUIT BOARD AVAILABLE FOR Rs.800/- without cell phone.
I am in Delhi India
Regards,
Ajay
Swagatam says
Hello Ajay,
I am sorry, presently I have discontinued the sale of the above item because the process gets too time consuming.
I am sure you would understand my inconvenience.
Thiru says
Swagatam,
I just visit your page first time today, I want to buy a tested "GSM Based Cell Phone Controlled Remote Switching PCB" from you. Please provide me the details like address etc .This is for starting a electric motor.
Appreciate your help!
Thanks and Regards,
Thiru
Swagatam says
Hi Thiru,
Thank you! However presently I have discontinued the sale of the above item because the process is too time consuming.
I am sure you would understand my inconvenience.
Regards
Engr Humayun says
Dear Mr. Majumder/ I am an Electronics and Electrical Engineer from BUET, Bangladesh. I have studied few of your articles. You are too intelligent and open minded to share your ideas which is helping people interested in electronics. It's really fantastic. Understand from the way that yu reply — you are too busy. what is your main profession? However I have some says to you- about your cell phone controlled switch circuit. The flipflop circuit that you have shwon have a mistake. The output of N2 should be connected to the inpt of N1 through a feedback resistor – which is missing. That is wy, many people is sending you the queries that the 2nd part is not working at all. It is a great mistake I think -which cost many time to investigate unnecessarily. However, it is really great.
Swagatam says
Dear Mr.Engr Humayun,
Thank you very much!
can you please identify which gates you are referring to as N1 and N2 in the above circuit, because the gates are not labelled in the above diagram.
Engr Humayun says
Hi Mr Majumder, how r u? it's nice to share your ideas.
LEKHRAJ SAINI says
hello sir,
i want purchase this readymaid circuit for my project work.
can u send me this circuit?
i will pay circuit charge+ shiping charge.
pls sir…
reply soon…..
Anonymous says
Hi I am Nayudu I want gsn controlled switch for my submersible pump…… pls let me know price and contact info……
Swagatam says
Please contact me here:
homemadecircuits@gmail.com
Anonymous says
Dear Swagatam,
I am not getting your response. I want to use the system to control my half horse power. As I am in remote place, I want to order ready made, tested CB. Pl let me know where to send the amount.
Rautela
Swagatam says
Dear Rautela,
I think i have responded to your previous comment….please contact me at my email ID
homemadecircuits@gmail.com, i'll provide you with the necessary details.
Thank you.
Rahik Chowdhury says
Sir, ur L1 buzzer 1000 turns = how much Henry, Can u tell me please? I am trying to simulate it Proteus and I am very near to final output.
Rahik Chowdhury says
Sir can u tell me ur L1 is 1000 turns = how much Henry. did u ever calculate?
Swagatam says
I don't know about the value of the coil, I have provided the picture, …..it gives an idea regarding how the original part looks like.
Sayad Hadia says
Dear Swagatam Majumdar
I am very happy because the circuit is working very good.
Thank you very much for help and mail.
But the cell phone works with all outside numbers although I have assigned (empty) tone for the cell phone and ring tone for recorded numbers.
Please tell me how can I solve this Problem
Thank you very very much
Swagatam says
Dear Sayad,
with a NOKiA 1280 this cannot happen because it's an in-built feature and will surely work as specified….did you assign it the way mentioned in the above article?
please test the cell phone in the usual way first, without connecting to the circuit.
regards.
Tusher Peris says
Hi Sir,
I am not that good at building circuit but I am really very enthusiastic to have a circuit like this. Can I please get it delivered to Bangladesh I pay the delivery cost. Please reply.
Best regards,
Tusher
Swagatam says
Hi Tusher,
I am sorry, the scheme is only for the indian customers, not from abroad.
the delivery cost can be as high as Rs.2000/- plus 800/-
PCS Rautela says
Dear Swagtam,
It is an interesting circuit. I live in a village in the hills and can't get the components. So I wish to buy your assembled one. What address I can send the draft.
PCS Rautela; 9899990967
Swagatam says
Dear PCS,
It will cost you Rs.800/- without the cell phone, only the circuit board with wire outputs, fully tested.
LEKHRAJ SAINI says
hello sir,
before i have connect transistors wrong.
now i connect rightly and i have not connect L1 coil.and RL1 is now oprates without miss call.
are buzzer coil is compulsary in this ckt?
Swagatam says
hello lekhraj,
yes L1 buzzer coil is compulsory….also connect a 0.1uF capacitor parallel to L1, it is not shown in the diagram but is extremely important.
Rahik Chowdhury says
Sir, also I need to know, what is about pin 11 of 4093 IC? Is that connected with any other pin or it was grounded.
Swagatam says
I am not sure how it will respond on proteus.
pin11 of 4093 is not connected, the entire gate is unused one.
LEKHRAJ SAINI says
RL1 does not operate……
i tried to increase gain of ckt using op-amp but RL1 doesn't operate.
what is problem in ckt?
tell me sir…
pls………..
Swagatam says
I am sorry I cannot troubleshoot your circuit, because I have tested this circuit thoroughly and have made many many pieces and sold it to my friends.
use a 1280 nokia cell phone only., assign the ringtone as explained.
Rahik Chowdhury says
Sir, is it possible to simulate in Proteus?
LEKHRAJ SAINI says
hi sir,
RL1 does not operate when i call.what's reason of this sir.
i check the circuit .
and what i do sir now…
and my ic is 4093BE. it is right or not?
Anonymous says
i cud nt find 0.22uF disc type capacitor, so cn i use 1uF/50V ceramic type capacitor?
LEKHRAJ SAINI says
hello sir,
i connect cap. parallel to R12 but again RL2 is operate without misscall when i connect to supply.
what i do sir………
i check circuit again ckt is exact as your circuit.only a diode is connect with T4 & T5.
Swagatam says
disconnect RL1 contact link from the upper circuit and then check.
By the way is RL1 responding to the missed calls?….
LEKHRAJ SAINI says
hi swagatam ji sir ,
i have made above circuit and also i connect diode series with T4 & T5.
and when i connect to supply RL2 is operate without mobile connect and motor runs.
now what i do sir pls help?
and sir in this circuit -ve 12v supply is connected to headphone of mobile directly.so sir if any risk inthis than tell me sir as soon as……………
thanks.
Swagatam says
Hi Lekraj,
connect a 100uF/25V cap in parallel to R12.
there's no risk with negative of battery connected to negative of the cell phone.
Valens Nizeyimana says
hello sir can i get how to design this circuit in software,i tried but that ic 4093 doen't found .
best regards
Sayad Hadia says
Dear Swagatam Majumdar
Thank you for your valuable Circuits.
Can you Please tell me how to use the circuit to energize the relay only , I don,t need the charger.
I want to understanding if I use the lower part only (((without the upper part and the coil L1))), it will energize the relay RL1 by missed call or not
Thank you very much
Sayad – Cairo – Egypt
Swagatam says
Dear Sayad,
RL1 will remain energized only as long as the call remains connected, when the call is cut, RL1 will also deactivate
ROHIT RAJ says
The same problem is faced by me… Only for lower circuit it can not enrgies the relay…
LEKHRAJ SAINI says
pls tell me what is the value of R10 in this project.
Swagatam says
it's 2m2, 1/4 watt
Dilandkl says
Ohh awesome!! =D
Thanks for the super fast reply!! Ill start making this rite away. Thanks Mr.Swagatam!!
Swagatam says
You are welcome!
Dilandkl says
Mr.Swagatam your circuit is activated when the phone rings and its deactivated the moment the phone stops ringing rite?
So is there a way that i can connect this circuit to a incandescent bulb and give it a missed call to switch ON the bulb and give another missed call to switch OFF the bulb
TY in advance
Dilan Leelawardena
TY
Swagatam says
Mr.Dilandki,
the above circuit will switch the load ON and OFF with every alternate missed call, so it's exactly as you want.
udayantandon says
Could you please clarify that if i want to use a gsm module instead of the nokia phone is it possible and what are the changes that i would have to make
Swagatam says
sorry that won't be feasible…
jirah888 says
can i put the LEDs in the load and remove the LEDs under T4 and T5 ??
Swagatam says
yes you can put the leds in parallel to the relay coil via 1K resistora
jirah888 says
how can i make this circuit simple to simulate it with proteus software ?
jirah888 says
what's it mean by "TO A OR B" ?
Swagatam says
see headphone pin in the diagram.
jirah888 says
we cant simulate this circuit using proteus software because some component does not have in proteus .. can you help me with this ?
Anonymous says
does the 2nd stage of the circuit activate? if we manually triggered a 5v DC
Swagatam says
yes it will activate manually also.
Anonymous says
First I must give you congratulations for publishing such a fantastic circuit !
I have built the said circuit. Up to RL 1 circuit is working very well i.e. RL 1 picking ON when hand set receives a call and RL 1 drops out / OFF when ring tone stops, but RL 2 is not picking up , LED connected across the coil of RL 2 blinks for very short time.. but RL 2 not picking up.
All connections of the circuits are checked several times, IC 1 also replaced then where should be the problem ?
Your early reply is awaited.
D. Karandikar
Thanks and regards
Swagatam says
Thanks!
see the 4093 circuit given here, build and check it separately and then connect it with RL1 of the above circuit
https://homemade-circuits.com/2011/12/build-these-simple-flip-flop-circuits.html
Gary N. says
Hi Swagatam,I just looked up your diode number,thats what I missed.
my apologies for the un-needed question,thanks gary n.
Swagatam says
My pleasure Gary! no issues….
Gary N. says
Hello Swagatam, I have been studying your schematic,i'd like to build
this for controlling engine heater in my truck. i saw in earlier post that
red diode symbol was LED, but I don't know what the black symbol represents.I can't seem to see them in materials list.
there are 3 up by and connected to IC1, and 2 others on drawing. Am I missing something? what are they? Thank you for your time, Gary
Swagatam says
Hello Gary,
The black symbols are diodes 1N4148.
Anonymous says
Hi sir,
could i used 12V/400 ohms relay?
Swagatam says
yes…
Anonymous says
Thanks for sharing the brilliant idea and circuit,sir.
*Are these 3.5 mm headphone pins available at the stores?
I feel it difficult to peel off the outer sheath of my headphone jack to take the pin out.
*What is the inductance of the buzzer coil used?Could it be replaced by one of the coils of a miniature driver transformer?
*Why T3 is a pnp transistor..?
I'am a beginner..
Regards
-Pranav
Swagatam says
Thanks!
yes it's an ordinary 3.5mm stereo jack because the nokia 1280 has a 3.5mm socket for the headphone outlet.
Swagatam says
you can try different types inductors for L1, I won't be able to specify the value because I haven't checked it.
PNP is used because an NPN won't work there:)
Pranay says
what is the value of r10
Swagatam says
2.2M 1/4 watt
Pranay says
can i use some number of half watt resister
harish r says
can i use this for borwell motor ….???
Swagatam says
yes….
Anonymous says
hai I build this circuit and when I try to operate it by calling nothing happens. I build this without L1. How can I check whether its working or not using DMM from stage to stage.Please help
Anonymous says
I am getting very low voltage from headphones (0.7-0.9mv)? also if this circuit is driving the relay on that much voltage so is this noise proof? i mean this much voltage will it get from surroundings as well so wouldn't it be affected by noise signals.
secondly could you plz send me readymade ciruit which you have already tested send me the cost as well because i am not able to find components here os your help will be much appreciated
Swagatam says
Your measurement may be incorrect, set the DMM to AC (mV range) and then measure.
The circuit is noise proof.
I am sorry, a ready made unit won't be feasible.
weng_fernandez1013 says
ok thanks sir…
weng_fernandez1013 says
hello sir..in behalf of our group, we thank you for your helpful circuit..we just made some additional components to upgrade the system and it is really working right now..we adopted it in our thesis project so we are happy to say thank you that we are blessed to have someone like you sharing a useful project like this without any cost..God Bless!!!
Swagatam says
You are welcome!
Anonymous says
bro
i got a problem, i just constructed the above circuit, just gsm section but there is one problem and that is the relay triggers when i just touch a simple wire to point A (C1) like its not doing anything with mobile ringtone even when i disconnect the handsfree from mobile and touch the handfree any wire with point A (C1) it triggers so what could be the possible problem, i think amplification is much high or what?? plz help
Swagatam says
That shouldn't' happen, did you connect the correct L1? try connecting a 0.1uF capacitor parallel to L1.
Anonymous says
does the input voltage supply can be a problem? i checked it and its 14volts so does it can be a problem? also even if i touch a finger with point A it triggers the relay. Also my 1280 nokia is delivering me only 0.7 to 0.9 mv? so is it enough for the operation or not
Anonymous says
Bro the above link is for just switching single output on/off
i need multiple outputs to be controlled so if you can help me doing that.
waiting for your reply
Thanks bro
Swagatam says
Sorry, no idea about such a circuit, it is possible with DTMF circuit, but DTMF circuits consume phone balance, so I don't like it.
weng_fernandez1013 says
sir can you give some cost benefits on this circuit?because we adopted it in our project…we thank you for sharing your own circuit and keep the good work..
Swagatam says
Thanks weng,
I leave this up to the users to decide the cost benefits of this unit, they can probably find it by comparing it with the conventional units and features.
Anonymous says
Yes you can take multiple output. You should switched another relay RL3 (3NO and 3NC, 230V AC) by RL2 contact and each NO contacts can operate one device. (You give output of RL2 to coil of RL3 and a nutral to second end of coil)
Brajesh Singh
Kanpur
Anonymous says
what will be the voltage at pin 8 & 9 of 4093?
thanks…
Anonymous says
Hi, led indicator of RL1 not totally off there is a shade of light left after every operation, what should i do? Thanks.
Swagatam says
connect it parallel to the relay coil with 1k series resistor..connect the emitter of T4 directly to ground.
Anonymous says
Hi Sir Swagatam, should i use heatsink for 7805 bcoz its getting hotter but then charging is good. another thing is how about overcharging? isn't an issue here? bcoz the unit will be permanently plug and maybe most of the time it will be on standby mode. Can you give me a circuit diagram or link for a more stable cellphone charger circuit that can be incorporated in this circuit please….. and also the green led indicator for RL1 didn't give me a blink unlike in your video, instead its just fading slowly but still the operation is responsive. should i change the value of resistor and capacitor? i've used what is stated in the partlist Sir. Thanks…
Swagatam says
Heatsink will be required for 7805.
all cell phones have an internal over charge cut off, so according to me there's nothing to worry.
connect the LED parallel to the relay coil with a 1K series resistor and it will switch off immediately as soon as the call is disconnected.
Anonymous says
Its done Sir thank u, what about these Sir, i removed the assigned tone in one of my number and made a call to modem several times and still both relays are responding even without the assigned tone and the modem is not ringing during a call, I thought that my L1 is not working Sir, i get it from an old 12v buzzer, it's a resistor-like shape as big as a 1watt resistor. i can't proceed designing a pcb bcoz of these queries Sir….JLC
Swagatam says
no that shouldn't happen, the circuit will not respond to any unknown number except the assigned numbers…even without L1.
Anonymous says
Hi Sir swagatam,
i just really dont know why my circuit is responding to unknown number Sir, which is should'nt be. using my multimeter i've test some resistor and found out that the value of some resistor is lower than what it should be, e.g. 220ohms reads only 215.2ohms, 1K – 93ohms only, is that matter Sir? i dont have any problem in the operation of my circuit Sir, i tried it on electric fan, t.v. and in my led strobelight and its works. only that its also responding to unknown number especially when i bring the cellphone that i use for calling nearer to the circuit then the more brighter the led indicator does. what should i do Sir? i really want it be done Sir… JLC
Swagatam says
please tell me your cell phone setting details…did you follow everything as suggested in the article?
Anonymous says
Hi Sir, Yes i follow everything Sir, i bought a brand new nokia 1280 for this project up to the settings Sir, set assign tone each and every contact saved in the phone and i have 3 of them, ringing volume is level 1, set ringing tone to "EMPTY", i also set to off everything from keypad tone, vibration alert, sms tones alert, warning tones backlight alert, etc.. BTW Sir my audio amplifier circuit is from this article and my flip flop circuit is from your other article "BUILD THESE SIMPLE FLIP FLOP CIRCUIT" posted by Hitman. i used the 2nd one using ic4093 Sir. Thank you very much Sir… JLC
Swagatam says
You have everything correctly, not sure why it's responding to unknown numbers.
connect a 0.1uF capacitor parallel to L1, that might solve the problem.
Anonymous says
Hi Sir,
Thanks a lot Sir the addt'l. capacitor helps not to trigger the audio amp relay ( RL1 ) by
unknown number yet my led indicator still glowing slightly each call from unknown number.
Can i increase the value of the addt'l capacitor Sir? what value? BTW i use PPC type.
Thank you Sir Swagatam… JLC
Swagatam says
you can try a 0.22uF disc.
Anonymous says
I also have the same problem it respond to every numbers i tried alot but didn't find any solution also tried the capacitor but still not working 🙁
Anonymous says
how much voltage will you get from the audio jack of the mobile when called???
Swagatam says
should be around 50 to 100mV
Anonymous says
are you sure that your circuit is correct?? will we get the output???? because no one has posted that they have got the output!!!
Swagatam says
get it verified from experts, this project is not for the noobs….
Anonymous says
Dear Sir, im done with the lower stage of the circuit, RL1 are now responding in every call i made my problem is the upper circuit is not working properly, RL2 is just giving me a click sound with its led just a blink in every call i made. what i mean is RL2 is staying in on mode. i've build and test the two stage of the circuit separately and checked every small details of connections and components according to your diagram but still a failure. dont get me wrong Sir but sometimes it comes to my mind that there's something wrong or missing NOT in your circuit Sir but in the diagram that being posted. i really want to build your project Sir but i am absolutely dependent on the diagram and advices from expert like you Sir.
Pushpendra Singh says
Sir i have made the circuit but i didn’t get result. would you like to help me on +919887095742. I Need urgent help.
Swagatam says
Pushpendra, sorry a telephonic conservation won’t be possible, the above design is thoroughly tested by me but please note that it will require an experts knowledge to complete this project and is not recommended for newcomers, so please move ahead with caution,
Swagatam says
You can incorporate any flip flop circuit stage with RL1….study the following circuits, you can try the first one if the second one seems difficult:
https://homemade-circuits.com/2011/12/build-these-simple-flip-flop-circuits.html
Pushpendra Singh says
Sir i have achieved the task but RL2 is making continue unwanted noice. What should i do ?
Swagatam says
Isolate the upper 4093 circuit stage entirely by disconnecting it from RL1, and check it separately by manually by touching R12/C5 to the positive line, this should alternately switch RL2 ON/OFf, first check and confirm this.
Pushpendra Singh says
Sir I tested 12 volt at C5 from N/O contact of RL1 but my LED across RL2 is continue glowing with vibration & sound in RL2.
Swagatam says
That means you have done some mistake in the flip flop circuit.
you can refer to the following articles and do the required corrections or make a different flip flop design using IC 4013
https://homemade-circuits.com/2011/12/build-these-simple-flip-flop-circuits.html
https://homemade-circuits.com/2012/05/make-this-easiest-flip-flop-circuit.html
Pushpendra Singh says
Dear Sir,
Thanks a lot for immediate response. Sorry for frequent queries but I need your guide.
My part 2 sometime works. But the LED glows when I touch my body part like finger or thumb to rest part of PCB. I think it requires PCB to be grounded. But I made all connections as per above circuit. I have two seperate PCBs with IC CD4093 for same connection but same problem persists for both. I think there is continue supply on Pin 4 then LED continue glows by making finger connection to PCB.
There is a problem to use IC CD4013 because I lives in remote rural area so its not available easily. If I order this online then it will take more than a week to deliver so i can’t wait.
I hope to immediate response.
Swagatam says
Pushpendra, if you compare the 4093 circuit from the other link I provided and the above 4093, you will find that a capacitor from the input trigger to ground is absent in the above design which might be causing instability, so you can add this capacitor and see the results.
see how C6 is added for stability in the 4093 design under this article:
https://homemade-circuits.com/2011/12/build-these-simple-flip-flop-circuits.html
Pushpendra Singh says
Dear Sir,
Now i completed almost 90% task. The only problem is that relay RL2 activates with single time trigger pulse but deactivates with multiple time pulse. I think there is some residual current at output. What should I do ? Please help me sir.
Swagatam says
Pushpendra, did you connect “C6” as advised by me earlier? If yes then now try connecting a resistor parallel to this capacitor..the value can be anywhere between 10K and 100K
Anonymous says
Whew!!! atlast its done, the first one works for me! thank you very much Sir for sharing such great stuff and also for staying online for us. GOD BLESS SIR SWAGATAM!….. JLC
Anonymous says
can i use any other mobile other than 1280?
Swagatam says
read the article and see if it matches with the given specs or not
Anonymous says
sir,i got L1 but its like resistor like shape can i use dat inductor?
Swagatam says
you may try it, but I am sure about its performance.
Swagatam says
i mean I'm not sure about its performance….
Anonymous says
Sir is there any substitute for 36SWG? what about a magnetic wire or a 22AWG copper wire for L1. thanks
Swagatam says
It would be correct to use only the specified component as discussed in the article, please see the updated diagram
Anonymous says
sir when the power supply is given both the LEDs are turning ON is that right??
Swagatam says
RL1 should stay OFF when power is swtiched ON.
Anonymous says
nokia 1616, but it does work sometimes, when I disconnect the coil… I dont know why, also respecting the Car security system, when I connect the d9 that comes from call back ckt doesnt work either, just when is without that connection and without the coil. I dont know what to do…
Swagatam says
I am not sure about 1616…Do exactly that's been suggested in the article, if you use different parameters it might not work….
Anonymous says
I am using that relay and the light turns a little bit on but not to the point of turning on the relay. Sometimes it does turn it but is not often, even though the tone is in the highest volume. Id like to have ur help. Which values must resistences and capacitors have so that it turn the relay of 400 ohms on with the lowest volume. I want to Put it in the Car system u made Thks in advance.
Swagatam says
which cell phone are you using, I used a nokia 1280 and worked perfectly.
don't use the "beep once" tone, use a musical tone for the assigned number.
keep the default tone to "empty"
Anonymous says
Dear Sir, I gathered all the component from different electronic shop in my place and thank God im done except for the L1 Sir. They dont have the 36SWG instead a 22AWG is what all they have. Can i substitute it for L1 Sir? if yes how many turn should i make using this 22AWG copper wire and can i wound it in an ordinary plastic tubing? ferrite core is another thing that very hard to find here. Please help me about this Sir Swagatam. im very excited to finish this wonderful project of yours. Thank you very much for sharing Sir Swagatam. God Bless!
Anonymous says
hello Sir, im done with your circuit on a trial/bread board a minute ago. only one component is missing Sir the L1… 36SWG are not common in my place. can i use #22AWG? how many turn it should be using 22AWG copper wire? can i make it a stand alone round shape coz ferrite core is also hard to find in here. or can i salvage a magnetic coil inside 12volt mechanical relay which is a magnetic wire? forgive me sir for asking too much. just want to satisfy myself by seeing this circuit working infront of me. hoping for your support Sir.
.
Swagatam says
I have updated the buzzer coil image in the above diagram, you would have to use the same type of component which is shown, making it by hand would be very difficult, and definitely not with a 22SWG wire.
Anonymous says
Hello sir
What can it be done on the circk in order to activate the relay of the amp crkt when the signal is pretty low. I'd like the phone not to sound so hard, it has 5 levels and Id like to set it at only one or even that it doesn't not sound at all. What would u recommend.
Regards
Swagatam says
if you are using a 400 ohm relay, then it should operate even at lower volumes……I used nokia 1280 and it worked like charm even at lower volumes with a 400 ohm relay.
venhin ven says
sir wats dat L1?
Swagatam says
small inductor as commonly used in piezo buzzers..
Anonymous says
Dear Sir,
How can i add a Potentiometer, to adjust the sensitivity rather than l1 coil.
Thanks
Swagatam says
L1 is not for controlling sensitivity…it's for filtering the unwanted RF signals, so it is required.
Anonymous says
Hi Sir can i Salvage a coil From an old buzzer for the L1? coz i had save some old buzzer but still in good condition. Thanks.
Swagatam says
Yes you surely can….
Anonymous says
sir,
do u have any circuit diagram for project using ic sn74lso2n or dm74ls156n or both
Swagatam says
presently i do not have these….
asokalokuwel says
Dear Swagatam !!
I made this circuit according to the above diagram.but the problem is amplifier part is ok.once i give a ring LED connected to amplifier part switched on. But when it becomes to the tiger part,LED connected to the T5 gives a blink.
(here I connected a table fan to the load part the problem is fan is switched on with the missed call but instantly it switched off.before the second missed call)
Sir Can u guess the problem?
thank you lot!!
Swagatam says
Dear asoka,
Refer to the second diagram and compare the two 4093 sections, it's a flip flop circuit which toggle position with each input trigger:
https://homemade-circuits.com/2011/12/build-these-simple-flip-flop-circuits.html
Anonymous says
Thanks! Ü im gonna try again 🙂 be back for updates 😀
Raj Mukherji says
Hi Swagatam,
Writing after sometime. 🙂
With reference to the project suggested by you I understand that it can be used to control any device remotely and since it is based on 'missed call' principle, therefore the user will not be charged a single penny per call.
Now, I am thinking of using it for the farmers in the rural areas for irregation purpose. Let me explain it for you:
I have noticed that the farmers use pumps for irregation purpose and most of these pumps are power driven. However, I have also noticed the below facts:
a. The electric supply is either not very consistent (there is power cut) or they get the supply for a specific time length per day during which the farmar has to run the pump
b. Often their farms/lands are miles away from home so they have to spend extra hours just for managing the pump
Your project can be of great value to address my second observation above and it will not add to any additional cost per call for the poor farmer which could have been if you had suggested this project using DTMF decoder.
However, I want to know if you can bring some changes to the present circuit of yours which will help the farmer to check the following:
1. If the electricity is available or not to run the pump
2. If the pump is actually running or not
I think the second point is achievable only when the remote mobile phone is configured to accept an incoming call from the user/farmer and once it does so, he can listen to the sound of the pump motor but it will cost him a call. However, if there is a situation where the motor stops working due to some reason/fault while the supply line is active, then how will it be possible for the user to get this information on his mobile phone?
Please see if you can add something to the present design to make my idea a fruitful one and it will be a wonderful project if for everything the poor farmer does not have to pay anything as call charges.
Take care.
Regards,
Raj
Swagatam says
Hi Raj,
Thanks for the useful suggestions.
A few relevant up-gradation can be done in the circuit, but it will make the circuit quite complex and difficult to build successfully by new enthusiasts.
But still, i'll try to present the modified version…possibly soon.
Take care
Regards.
Vishal Sherathiya says
Have you done any modifications?
I have another idea over missed calls.
Generally in farms there is problem of electricity.
In this case, please note:
1. If farmer gives a missed call to gsm module, the motor starts.
2. When electricity is cut by government, motor stops.
3. Electricity comes back but motor stays off.
4. Farmer is not aware of steps 2 and 3.
5. Farmer gives a missed call to gsm module to stop the motor, but actually he gets his motor started. And here our system laks intellegence.
So, a possible solution would be:
When farmer gives a missed call, then motor should start. When farmer gives a missed call again, the motor should stop. But this time he should get a missed call back from gsm Module to the mobile he called. Also when electricity fails there should be a battery. At the time of electricity cut, the farmer should get aware by giving him a missed call. Can you implement such a logic in your newer version?
Also the motors used by farmers are 3 phase. So, there should be some thing that a farmer should know if he has electricity available in all the three phases or only single phase.
Swagatam says
the above design is just a basic concept for understanding which can be enhanced in many different ways:
electricity failure problem can be easily tackled by adding a small battery back up for the circuit, so that the missed call operations from the user works perfectly regardless of the mains availability.
the call-back alert feature has been already elaborately discussed in one of the similar application concepts as given below:
https://homemade-circuits.com/2011/12/build-homemade-gsm-car-security-system.html
the feature is also separately discussed below which could be easily included in the above design
https://homemade-circuits.com/2012/04/make-this-cell-phone-call-alert.html
Anonymous says
Excuse me….. Is the positive sign above rl2, same with 14 13 12 of IC1 refer to positive of the supply?? Thanks!
Swagatam says
Yes all (+) signs are common and should be connected to a DC12V supply.
Anonymous says
When i turn it on, the phone (N1280) charges. But ive got some problems in the relays 🙁 they just ….. Turn On as soon as i apply the SMPS 🙁
Anonymous says
sir i have got the same problem.. can u giv us some suggestions to rectify???
Swagatam says
how can T3/T4 switch ON with a DC input?????????
Anonymous says
When i connect the voltage source, both relays activate. 🙁 icant find the problem 🙁 HELP.
Swagatam says
The circuit is absolutely correct, and I have tested it thoroughly so I am unable to troubleshoot your problem.
Remove the headphone and then check.
Anonymous says
The schematic above is exactly the same as what you worked with right? 🙁 even without signal from the phone, both relays and leds turn on. 🙁
Anonymous says
The leds and relays shouldnt activate when you apply the SMPS right? :/
Swagatam says
I think there's something wrong with your connections or components. check them properly
Anonymous says
Both LEDs and relay shouldnt activate when supply is turned on right? 🙁
Anonymous says
Leg 11 in ic1 has no other connection? 😀
Swagatam says
that's right, both relays shouldn't activate.
Raja King says
i want to connect the circuit to a 3 phase motor for irrigation purpose ……… can the relay be triggered and switched on the motor, for a long time if the cal will be ended frm the mobile…. i need ur reply please please reply soon
Swagatam says
The above circuit can be used for any electrical equipment, only the relay rating will need to be modified as per the load.
The flip flop made from IC 4093 will hold the relay switched ON permanently until the next call is made.
weng_fernandez1013 says
2nd stage not working..is the relay stay on when you stop the misscall in 2nd stage circuit?
Swagatam says
2nd stage is a flip flop, so RL2 will change position with every alternate activation of RL1 or the given missed calls.
Muhammad Khalil Anwar Nizami says
GSM module if use then ,then what happened,you have to display the project,which is much beneficial for incomers,GSM based,GPS,.please sir give us that idea.
Swagatam says
Sorry, Presently I don't have a GSM/GPRS module based circuit…
Muhammad Khalil Anwar Nizami says
sms based automation you not discuss,why sir?
Swagatam says
yes you are right, the above circuit will operate only a single load at its output…….
sms based operation will involve gsm module.
Muhammad Khalil Anwar Nizami says
ok sir,and how much devices can control this circuit,only on for one number?
Muhammad Khalil Anwar Nizami says
as you given the circuit,how can control 2 or above devices usin a same particular number,like i set a number of mine at receiving side,and when i call,the operate section operate only one relay.
AM i right,if not then told me.please,have a main dificulty.
please sir
Anonymous says
Any specs for LED? 🙂 THANKS A LOT!
Swagatam says
red 5mm 😀
Anonymous says
And by the way the ic1 displayed in the diagram is in its top view right? 😀 sorry im a newbiee. 🙁
Swagatam says
yes:)
Muhammad Khalil Anwar Nizami says
confusion:
sir if i call the circuit,wht the relay on time and off time,can you explain?
Swagatam says
I have explained everything in details under "Understanding the Schematic Diagram" section….please read it…
Anonymous says
Sir you said in the previous comments that all diodes are 1n4148 diodes. So the ones below T4 and T5 are LED's, right? Ü
Swagatam says
Yes those are LEDs 😀
Anonymous says
Would it work just fine even without the LED's? 😀 just for the preliminary run 😀
Swagatam says
yes, it will work, connect the emitters directly to grnd 😀
Anonymous says
The value for r13? 🙂
Swagatam says
100 Ohms 😛
Anonymous says
1/4 watt? 🙂
Swagatam says
yes 😉
Anonymous says
What's the value for r13? Ü
asokalokuwel says
hello sir,
Sir Do you use any LEDs in the above circuit?? I mean as indicators?
I saw Diode shape item with three parallel lines,It makes me to ask this question!!
Swagatam says
Hello Ashok,
Yes, the RED diodes are indicator LEDs.
Anonymous says
Sir are the capacitors below the ic7805 disk types? 🙂 thank you —
Swagatam says
no, they are electrolytic types
Anonymous says
Thankyouu! 🙂 can't wait to finish this project 🙂
Swagatam says
you are welcome…:)
Sam Devil says
Sir is ground mence -ve
Anonymous says
hello sir,
is this circuit correct or not of link below? plz tell me
img607.imageshack.us/img607/8682/remotecontrol.gif
and how can i modified this circuit for control/swictching(on/off) more than one appliances as a way, i wish by one remote only,
thnx and regards
Swagatam says
Hello Ahmed,
I have replied you in the previous comment:)
Anonymous says
and for the R10 value? 🙂
Swagatam says
2m2, 1/4 watt 🙂
Maaz Gilani says
sir please give me the correct link of this diagram.
Anonymous says
hi sir,
1: i hv a circuit from internet and i want to confirm that if it is correct or not? plz check this link below,,,
img607.imageshack.us/img607/8682/remotecontrol.gif
how can i modify this circuit for switching more than one appliances separately by one or same remote control ?
for example : if if want to switch on fan and switch off tubelight of my room by same remote with different buttons?
ahmed
Swagatam says
Hi Ahmed,
The circuit will work,
you cannot control more than one load independently here…..it can be done but only one will be ON at a time…… you can control 10 loads (max) in sequence one afer the other using IC4017.
Anonymous says
Sir if I may ask, what is the value of R10? 🙂 and for the o.22uF capacitor. I assume I could use 0.1uF/25v ceramic cap? 🙂 THANKS!
Swagatam says
I have answered your question in the above comment, use two 0.1uF in parallel for 0.22uF
Anonymous says
Sir if I may ask, what is the value for r10? 🙂 and for the disk type capacitor, can I use ceramic caps like 0.1uF/25volts? 🙂 THANKS!
Swagatam says
Yes ceramic cap will do…..R10 = 2M2
Anonymous says
Sir, what's the value for R10?
Swagatam says
R8 and R10 are both 2M2
fadhil427 says
ok sir thanks.will try it and get back to u soon.thanks again!
fadhil427 says
hello sir,
what should i do if i want to make the cell phone to trigger my remote gate? can i just directly connect the speaker wire from the phone to the remote switch.i just need the phone to give me a 1 second trigger to the remote switch.i could just set the ringtone to "beep once" when i call it and call it again to shut the gate.
will it work like that?
Swagatam says
Hello Fadhil,
You may do it by connecting the RL1 contacts parallel to the remote switch.
Anonymous says
What are the diodes near T4 and T5 with 3 small lines over it. Is it an LED
or a Photo diode?
What's its value?
*Thanks
Swagatam says
All are 1N4148 diodes
weng_fernandez1013 says
why in your video, there are more than 2 relays?
Swagatam says
The extra relays are for operating the central lock in a car door…
weng_fernandez1013 says
thanks for replies..hope i'l do the circuit correctly..i'l find first the parts for better output..i'l message you for further question and hope you will help me..regards..
Swagatam says
You are welcome!
Anonymous says
Hi,
Thanks for your article and I am using your circuit for my daughter's exhibition. In Abu Dhabi, I could not purchase 0.22uf capacitors. Is there any alternatives possible? Also, as per the substitute list, I could understand that I can use BC558 or BC559 instead of BC557. Is that correct?
Appreciate your feedback..
Shafir
Swagatam says
You are welcome!!
You may try any closer value capacitor, such as 0.1uF, 0.47uF, 0.33uF etc….any one will do, even 1uF will work
Yes, 559, or 558 will also work in place of 557.
Regards.
Anonymous says
How can i get the L1. Are they available in market.
what are the other inductors used in circuit. are the same as L1
Swagatam says
yes they are available in market with the name buzzer coil, these are extensively used in piezo electric buzzer transducer circuits.
weng_fernandez1013 says
my circuit wont work..i dont know why..do you have step by step tutorial for this…?
Swagatam says
The circuit is very straightforward, you should be able to make RL1 work immediately for sure…….there's nothing so complicated about the circuit.
weng_fernandez1013 says
thanks man..
Anonymous says
Plz give the schematic diagram of the circuit………
Swagatam says
check it now…
weng_fernandez1013 says
what is the substitue for bc547 and bc557??i cant find it..pls help..thanks
Swagatam says
Refer table2 in the following link:
www.sentex.ca/~mec1995/circ/tuptun/tuptun.htm
weng_fernandez1013 says
thanks sir…can i use 3904 and 3906 rather than those in the table?
weng_fernandez1013 says
Is there any substitute for IC-4093?thanks again
Swagatam says
If their hFe range is around 200 to 300 then you may use them…
Swagatam says
there's no substitute for 4093….
weng_fernandez1013 says
really…,i cant find 4093..what if i use 7400 nand gate,is it possible?
Swagatam says
you may try 74LS132,,,,will require strict 5V for operations.
7400 will not give good results.
Anonymous says
Dear for controlling we have to call the desire controlling mobile set, or without calling that mobile I think it based on DTMF tone system
BR,
Obaid
CodeSecret says
Hello sir,I want to purchase this circuit. Please send me total cost including shipping cost and mode of payment. I am from ahmedab,gujarata..
Thanks
Mahesh Patel
mahesh_s_patel@yahoo.com
Gelo Nuev says
yup.. not based on DTMF