A programmable timer is a device which can be used for switching a load ON and OFF after predetermined delays as per the requirements.
The delay timings are adjustable according to the users personal specs. The ON time delay and the OFF time delay are independently settable and this facility becomes the most important feature of a programmable timer circuit.
Using Versatile IC 4060
In this page we will discuss a very simple yet reasonably useful timer circuit diagram whose ON time and OFF time settings are independently adjustable through ordinary pots.
The idea becomes so easily configurable due to the versatile IC 4060 which require minimal number of component for getting the unit running.
Looking at the CIRCUIT DIAGRAM below we can see that two inexpensive IC 4060 have been wired up as two independent timer modes.
However though the timing settings are independent for the two sections, these are coupled with other such that their initialization become very much interconnected.
Basically both the configurations are similar and have been rigged in the standard counting modes of the IC 4060 devices.
How the Circuit Functions
The output of the upper IC is coupled to the reset input of the lower IC via a transistor in such a way that once the upper IC's output goes high, it triggers the lower timer into operation.
The lower IC then starts counting and when its output goes high, it halts the upper ICs counting and resets it to its original state and the process is initiated back from the start.
It simply means that as long as the upper ICs timing does not lapse the lower IC remains idle, however once the upper ICs timing lapses and its output becomes high, it switches the output load as well as the lower ICs operation.
The pot associated with the upper IC can be used for determining after how long the load will be switched ON, while the pot associated with the lower IC is used for determining how long the load remains in the switched ON position or simply after what time it should be switched OFF.
Update:
The LED positions have been changed in the following updated designs, because the earlier LED positions were conflicting with the relay operations, and therefore the positions have been relocated for ensuring foolproof operations.
Circuit Schematic of a Versatile Programmable Timer
PCB Layout
Video showing the proposed 2-stage programmable timer circuit with LEDs
Using a Start Push-Button
The above design could be upgraded with a push-button to facilitate a push button start. This further ensures that the timer shuts off completely in case a power failure occurs while the circuit is operational, which in turn ensures that crucial loads like heater, or geyser are completely turned OFF during such situations.
Customizing the Above Concept
This circuit of a flexible programmable timer circuit explained in this article was designed by me in response to a request by Mr.Amit. Let's know more about the request and the circuit details.
Technical Specifications
"I need a circuit for my auquarium where it should do the following
it should switch off the lights at 10:00 pm and start at 7:00 am daily + switch off the light at 12:00 pm daily and switch up at 6:00 pm back.
this will help to make my fishes live longer. 🙂
Thanks in advance.
Amit desai"
The Circuit Design
So here's the circuit that I came up with. As the name suggest, the timer is pretty flexible and may be adjusted to produce any desired time periods, according to the above requested format.
The circuit consists of four identical stages, made up of the IC 4060 timer configuration. Te timer sequence begins from the IC at the top left corner.
When power is switched ON this IC starts counting. Depending upon the setting of its pot, the IC triggers after a certain period og time interval.
This switches ON the relay and the driver transistor BC547 which consequently switches OFF the connected lamp. The stage gets latched with the help of the diode connected across its pin 3 and pin 11.
The above triggering  also switches another BC547 transistor which connects the reset pin of the next IC 4060 to ground which initiates this stage also.
After a predetermined time, this IC also triggers its output at pin3 and gets latched by the corresponding diode, however this actionsends a feedback signal to the relay driver transistor, instantly switching it off and restoring power back to the lamp so that it lights up again.
Just as the above actions, the sequence further proceeds and switches ON the third IC 4060 in the line which counts the set time interval and pulls the relay back to OFF position via the diode connected to the collector of its bc547 transistor, such that the lamp again gets switched OFF.
As soon as the above triggering happens the last section at the bottom right corner switches into action and counts as per the setting of the respective pot, until the ICs output becomes high, this high reset the the first IC and switches ON the lamp once again so that the process may be restart the cycle all over again.
The pots may be increased to 3m3 for generating higher time interval periods, so is true with the respective capacitors.
Circuit Schematic
How to Adjust and Set Up
The timer may be adjusted as per the sent request, in the following manner:
If we consider the first timing sequence to begin at 7am and end at 12pm, means the upper left timer's P1 needs to be adjusted such that it activates the relay and switches off the relay after exactly 5 hours.
For keeping the lamp switched OFF in the above position and switch it ON back at 6 pm we now adjust P1 of the upper right timer section such that its output triggers after another 5 hours. This switches ON the lamp again.
The above situation needs to be kept intact until night 10pm, which is about 4 hours of period, therefore we adjust the lower right timer's P1 to get it triggered after 4 hours of time interval.
Finally, for initiating the above procedure back again the next morning at 7am, P1 of the last timer at the lower right is adjusted such that it resets the first timer after 9 hours..... and the cycle repeats.
For making the circuit work according to the above specified timing pattern, after adjusting the respective hours, the unit should be powered or switched ON exactly at 7 clock in the morning....rest will automatically follow.
musa israel says
Kudos for the great projects sir! I am Israel you have really inspired me through your home made circuits blog. i am a student and i would like to build an incubator circuit that checks humidity say at 22, temp at 38 celcius, and automatically forwards and reverses a 12v motor
thanks my email is musomaji@gmail.com
Swag says
Thank you Israel, I have one similar Arduino based circuit, which you can find here
https://homemade-circuits.com/incubator-using-arduino-with-automatic-temperature-and-humidity-control/
Suleman Habib says
Sir i want to use this circut to control water heater but it start automaticly with power on i need a programable timing circuit that start count with push button and dont start after power cut.
Swag says
Hi Suleman, in this circuit the relay will not start on power switch ON. he relay will switch ON only after the upper IC has finished counting and the upper IC’s stipulated time has elapsed.
There may be some fault in your circuit or it could be due to the low capacitor value at pin#12 of the upper IC, I have changed it to 1uF…please use this new value and check again
Swag says
For the push button the circuit will need some modifications…I’ll try to update the new design soon…
Suleman Habib says
I made this circuit several times again and again but i think there is something wrong in the diagram because both two ic work Properly if i don’t connect the lower ic pin 3 to upper ic pin 12 with 1N4148
If i connect it damage the ic
Swag says
The circuit is thoroughly tested by me and there’s nothing wrong that I can see in the above drawn diagram
Pin#3 from the lower IC applies a positive logic to pin#12 of the upper IC so that the whole system can reset back to the original condition, how can there be anything wrong in this process??
you can try this manually also, just touch the pin#12 of the upper IC to the positive supply with a wire, and the IC will reset back to zero.
make sure your supply input is not above 12V ideally, because 15V is the maximum recommended level.
If your IC is getting damaged when pin#12 is touched to (+) supply then your IC is definitely faulty or duplicate in quality.
Suleman Habib says
is it possible to use one 4060 and one 555 IC please give me diagram
I need a circuit that on for 10 min in an hour Please help…….
Swag says
it is possible, but IC 555 will give inaccurate delay results and will be suitable only for short delays.
Swag says
10 mintues is OK for IC 555, i’ll try to update it soon.
kanagaraj says
dear sir i want 3 hour timer circuit when power is on the timer wants tostart counting after 3 hours the output relay comes to activate after that i will reset the circuit after resetting the circuit the counting will repeat the same proces
Swag says
dear kanagraj, you can try the following concept
https://homemade-circuits.com/how-to-make-simple-versatile-timer/
Ani94 says
Hello Swagatam. I am your new subscriber. I already made some of your circuit design. And i want to say you thanks.
Swag says
Thank you and welcome to my site Ani, I am so glad to have you on board
K. Fernando says
Sir,
I would like to refer to a post for which you have replied as follows.
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edwin siy says
December 3, 2015 at 8:48 am
Good day Sir,I build this awesome circuit but the problem started when I switch on the red led and relay instantly activated while the green led light up after 5 sec. and goes off after 5 sec. but the red led and relay still energize. The green led goes on/off 5 sec. interval continuously with both red led and relay energized. The only components I change are the ff. P1 to 2m and R2 of the lower circuit to 10k and pin#9 of the lower circuit to 0.1uf ceramic cap,the rest stay as is. I know by the way I explained,you already pictured what went wrong. Thank you
Reply
Swagatam says
December 3, 2015 at 2:42 pm
Good day Edwin,
red LED will light up when the circuit is initialized, this is correct, but this should not activate the relay because the BC547 is not supposed to activate when the red LEd is ON…it looks contradicting.
when green LED lights up, the red LEd should shut off….so again the result is incorrect in your circuit.
try increasing the setting of the pot and check the response in a slow motion to read the operations correctly….there could not one but more issues in your circuit which will need to be traced and eliminated…
Reply
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Sir, this is the same problem I came across. I also changed the C1 & C2 to 0.22uF and P1 & P2 to 500K since I needed 10 minutes ON and 20 minutes OFF sequence.
As mentioned in Mr. Edwin Siy’s post, the relay and the red LED keep on activated all the time while the green light comes on and goes off to the set time interval. Further I notice, once the green LED is ON the brightness of the red LED decreases.
Sir could you please give me an advice and help me to solve this problem.
Thank you.
Regards.
Fernando
Swag says
Hi Fernanado, please understand yourself and try to figure this out….if the red LED is ON, that means pin#3 has to be at zero logic.
If pin#3 is at zero logic how can the BC547 conduct? because the BC547 will require at least 1V to switch ON.
My guess is that your IC is not of good quality and due to which it might be leaking some voltage while the upper IC is in the counting mode….
you can probably remedy this by adding a diode in series with the emitters of both the BC547 transistors….anode will connect with the emitter, while the cathode to ground…do this and check the response.
also increase the value of the 0.1uF cap at pin#12 of the upper IC to 0.33uF or 0.47uF so that the IC gets correctly reset when the power is first switched ON.
K. Fernando says
Sir,
Thanks a lot for your prompt reply and for your kindness. I shall try your advice.
Thank you.
Regards.
Fernando
Swag says
You are welcome Fernando!
Rishabh says
Hi sir
Myself Rishabh, sir I made this circuit but the problem is that the green led along with the relay turns on when I disturb the wire connected between voltage source and the circuit or when I shake the circuit board , this is a weird please help me.
Swagatam says
Hi Rishabh, there could be some kind of loose connection in your circuit, i hope you have made it by soldering and not on a breadboard…please check the solder connections and resolder the joints if possible…
Rishabh says
Hi sir the circuit is not working properly only the red led is glowing when the p1 is in lowest value , please help.
Swagatam says
Rishabh, Please go through all the comments and try to solve the problem by referring to them…I cannot troubleshoot your circuit fault because do not know what mistake you might have made in it…it will need a practical checking….
Or you can first make two individual 4060 timers separately and check them, if you succeed with them, then you could combine them as per the given figure for the final result…