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Controlling Motor with a Cell Phone

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The following article describes a very simple circuit idea which can be used for controlling a motor's rotational direction i.e. for moving it either clockwise or anticlockwise through alternate miss calls from your cell phone.

The Circuit Concept

I have already discussed a novel cell phone controlled remote switch circuit where the unit can be used for switching an electrical gadget through the users cell phone. The user just has to call the remote system which responds to the blank calls  and generates the required alternate switching of the connected gadget.

The same circuit has been used here also, the output is appropriately modified such that now the unit becomes suitable for toggling the rotation of a DC motor.

The circuit shown below can be used for controlling a motor rotational direction, let's try to understand it's functioning details:

The lower section of the diagram consisting of T1, T2, T3 and T4 along with the associated components forms a simple high gain audio amplifier circuit.

This circuit is used for amplifying the ringtone generated by the attached modem cell phone unit.

How it Works

The modem cell phone handset is an ordinary NOKIA 1280 cell phone which is permanently integrated with this circuit.



The above modem cell phone  uses a prepaid SIM card and thus it becomes a self contained receiver module.

When this modem cell phone is called by the owner's cell phone, its ringtone activates and gets amplified by the above explained tone amplifier stage.

The amplified signal becomes powerful enough to triggers the relay RL1.

This relay holds or remains activated as long as the call stays connected, and breaks when the call is disconnected.

RL1's N/O contact is supplied with a 12v trigger to the adjoining stage which is a FLIP/FLOP stage, made by using four NAND gates from the IC 4093.

With every alternate missed calls from the owner's cell phone, the modem cell phone signals the tone amplifier, which activates RL1, and RL1 in turn flips or flops the IC1 circuit.

The output of the flip flop is connected with a relay driver circuit which is attached with two relays RL2  in parallel. You may use a single DPDT relay also for better convenience.

The contacts of the relays are configured in such a manner that flipping them produces opposite movements for the motor that's integrated to them.

The mains supply to the relay and the motor is taken from RL1, which means the motor flips with every subsequent "missed calls" and remains activated until the call stays connected, and then halts.

The circuit can be modified in many different ways as per the users specifications.

The modem cell phone should be appropriately assigned with a particular continuous ringtone while the default ringtone should be assigned to "empty", tis will make the unit immune to unknown numbers or wrong numbers, and the owner will be the sole controller of the attached circuit and the motors.

Parts List

All resistors are 1/4w 5% CFR unless otherwise stated.

R1 = 22k
R2 = 220 OHMS
R3,R11,R12 = 100K
R4,R6,R7,R9 = 4.7K
R5 = 1K,
R8 = 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 = RELAY 12V/400 OHMS SPDT
RL2 = Relay DPDT 12V/400 ohms
L1 = small buzzer coil, small choke or similar.
JACK = 3.5mm AUDIO JACK
CELL PHONE MODEM = NOKIA 1280

Video clip showing the remote control operation of the circuit using a cellphone.

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Comments

  2. Sir I want to make a wireless 3 phase mobile starter for agricultural purpose ….and I'll use for projects also…Sir plz…give me its ckt ingo and its ckt components details…..and how to design it

    Reply

  13. hi.. How can i use above circuit to start and stop small dc motor.. where do i connect motor? do i need any other additional components? can any other phone can be used other than nokia 1280. Thank you..

    Reply

    • hi. i have checked the above link you specified but i am bit confused where and how to connect dc motor it would be very useful if you could tell me that. Because i am confused with the AC main supply in that circuit and load because dc motor does not require any ac supply as per my knowledge. if you could tel me in very perticular where to connect the motor. Thanks in advance.

      Reply

    • Hi. Is dc input is mandatory? Or can I directly connect two wires of motors to normally open pin and common pin relay will that work? If not any polarity is to be taken care while connecting dc input and motor. Thanks in advance

      Reply

    • without DC input how would the motor get its supply??

      the polarity can be anyway round, depends which way you want the motor to rotate anticlockwise or clockwise.

      Reply

    • Hi. Thanks for clearing confusion. I did as u said but it dint work. I have connected positive 12v supply to one end of dc motor and other end of dc motor to relays normally open terminal and I have grounded the common terminal of relay is this the correct connection? And how can I debug my circuit?

      Reply

    • thanks, so you mean to say that you are not able to figure out how to make the relay contacts operate a motor?? I am sorry then you must first learn all the basics and then come back here, because this project could be far too complex for any any newcomer.

      the relay contact has to operate from N/C to N/O for the motor to work…

      Reply

    • all are standard parts, nothing is specially rated..for example all resistors are 1/4 watt, all capacitors are as per 12V supply etc….only the TPTT relay will need to be rated as per the motor current specs.

      Reply

    • Swati, sorry I did not understand what you meant by design basis….you will have to replace RL2 with a 3 contact relay or a TPTT relay in the above circuit for controlling a 3 phase motor.

      Reply

  20. Hello Sir…I want to switch ON & OFF AC 3 phase motor…
    Is this circuit suitable for my requirement?
    And if there are any changes in this circuit ….
    Plz tell me as early as possible…

    Reply

    • Hello Swati, yes the above circuit can be used for the purpose, the upper two relays will need to be replaced with a single relay having three sets of contacts which can be then wired across the three wires of the motor and the AC inputs

      Reply

  21. Hello Sir…I want to switch on & off AC 3 phase motor with every subsequent missed calls. Is this circuit suitable for my requirement?
    And if there are any changes in the circuit..
    Plz tell me as early as possible….

    Reply

    • Dear Chandan, yes it can be done by using DTMF technology, however I don't like the concept because it consumes your cellphone's "talk time" and therefore the procedure is never free of cost.

      Reply

    • use all the equipment wisely…for example use TV sets with less contrast, use fridge at lower cooling adjustment, same with ACs and fans….you will see 50% reduction in the bill..

      Reply

  26. thanks for your valuable reply. i got it what you are saying but i want to connect this circuit to the 3 phase motor starter so that im able to on off motor connected to starter..

    Reply

    • if you have a starter with your 3 phase motor then you wouldn't require the upper 4093 flip flop stage, you can simply connect RL1 contacts in parallel with the starter switch.

      make sure that you end the call immediately as soon as the motor starts, so that the supply is fed only momentarily to the starter relay.

      Reply

    • thanks Vinod, yes you can use the above circuit with 3phase motor, ignore the shown relay contact set up for the motor, for your application you will need to use a relay with 3 changeover contacts, or TPTT relay and simply connect all the 3 contacts in series with the motor wires and the 3 phase mains input.

      Reply

  30. hai ,
    I want more explanation about ON/OFF cycle ( What I meant is whether the motor will sustain for ON for long . How it is controlling the ON/ OFF. There is no explanation for IT.) From the explanation what I understood is the motor will be working only during the ringing period of the mobile .It will be sustain only for few second .

    Thanks
    Sreelal

    Reply

    • The motor will run either clockwise or anticlockwise alternately, in response to the toggling of RL2….the motor will not stop until power is switched off.

      Reply

  34. Hi sir its been 5 days since I have carefully doing this project and checking it carefully RL1 runs really smooth and has no problem at all, but RL2 has really giving me a big problem, sometimes relay works fine sometimes it wont, if I`m correct R11 and R12 are full down voltage resistor isn't it?, I also change IC 4093 4 x just guessing that this has factory fault but still same problem giving me, I have carefully double check my layout before posting here, but RL2 really dont work properly, what might be the problem of this?, I really do hope to finish this project, can you help me check the circuit diagram what probable cause we are having now, cause lot of us has the same problem running RL2 and regarding RL1 it is running well.. Thank You So much, more power to you..

    Reply

    • The mortor has no connection with the modem, you can clearly see that the motor wires join with the positive/negative supply via the relay contacts and no connection with the modem.

      Reply

  44. sir, in this ckt the two led which are connected to the relays are glowing but the motor is not rotating.what is the meaing tha the led's are glowing and relay is also producing sound that means it is also working but motor is not rotating.there is some error in this circuit?please help its really urgent.

    Reply

    • The diagram correct, in the shown position the (+) passes through upper relay N/C into the motor and comes out of the motor to pass through the N/C of the lower relay to (-), in this condition the motor will rotate in one direction,
      now if the relay is activated, the opposite will happen and the motor will rotate in the opposite direction.
      Did you connect the N/C and N/O of the two relays to ground(-) as shown in the diagram??

      Reply

  47. Dear swagatam,

    i am trying to build 1st part of this circuit only but not able to toggle that relay i am building only that area which includes relay, IC 4093, BC547B & etc i didn't build receiving section but not able to understand which wires has to get sorted to trigger the relay. i tried to sort wire coming from R12 with positive wire of the supply but it didn't worked. please help me out ASAP

    Thanks in Advance

    Reply

    • No, speaker signal from cell phone is not negative based, here we require negative based signal, meaning one terminal should connect with the negative of the supply.

      Reply

  52. Brother, why you take RL2 supply from Rl1? Should it work? How the Relay RL2 remain halt in it's new position after disconnecting call? Please check and help me to confirm.

    Reply

    • In this circuit the motor can be stopped only by switching OFF power, the cell phone "missed calls" will only toggle the motor direction, it won't halt the motor.

      Reply

  54. Hello Sir,
    Thank you for your highly valued lecture. If possible, Can you help me to know how to use this circuit but with little modification so that motor need only one missed call to stay in one state and if I wand to change its state I send an other only one missed call.

    Reply

  57. I did this circuit but failed. I use L1 for 32 turns insulated copper wire, is this value important in this circuit. Can I use cfl lamp chock proper for this circuit, kindly pls give me all for reply

    Reply

    • Hi Lekhraj,

      R10 is 2m2, buzzer coil is a ready-made coil which is normally used and found in 2/3 wheeler flasher/buzzer units, you can open one such unit and retrieve it from there, or ask your local electronic dealer.

      Reply

  59. Hi swagatham,I'm your big fan….I need an information about how to make ordinary pcb board(dot type) to our required circuit board….plz help me

    Reply

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