The post narrates a simple yet highly accurate adjustable 1 to 10 minute timer circuit with display. The idea was requested by one of the dedicated readers of this blog.
Technical Specifications
I am trying to build a circuit to help me with giving speeches. I have a bunch of parts already and I would like to use them if possible. I want it to have an On/Off switch to power the circuit and a Start/Stop button as well as a Reset button.
I would like for it to light a Green LED after 5 mins, then turn off the green LED and light an Amber LED at 6 mins, and then turn off the Amber LED and light a Red LED as well as sound a buzzer at 7 mins.
I would also like to have a seven-segment display show the elapsed time. Let me know haw feasible this would be. Thanks.
The Design
In the shown 1 to 10 minute timer with display circuit, IC 4060 is configured as a 1 minute clock generator which is acquired at its pin#3.
The IC 4017 is wired in its ususal decade counter mode wherein its outputs shift a logic "high" across its pin3 to pin6 in response to every single minute pulse by the IC 4060 at its pin#14.
As requested three LEDs are positioned for indicating the elapsing of 5 minutes, 6 minutes and 7 minutes in sequence across the pin1,5,6 respectively, with the relevant selected colored LEDs.
For setting up the IC 4060 with 1 minute intervl at its pin3, we initially use a randomly selected low value capacitor for Cx and then note down the interval at pin3 for this capacitor.
Once the interval is known, the value of Cx for achieving 1 minute time may be calculated with the following formula:
Cx/Cr = 1/Rm
where Cx = required value, Cr = random value capacitor (in uF), Rm = time interval noted from Cr (in seconds)
The reset button at pin15/12 of the ICs can be used for resetting the circuit to original state.
Once the final selected interval is elapsed, the circuit latches itself and freezes by supplying a "high" from the relevant IC 4017 output to pin11 of IC 4060.
The red LED at pin15 of 4060 IC indicates the counting process by blinking the connected LED until the pin#6 of IC 4017 goes high.
The proposed circuit can be used for indicating any time interval from 1 to 10 minutes by using all the outputs of the IC 4017.
For getting different ranges of time intervals across each pinout of the IC 4017, the IC 4060 clock can be set with the desired time ranges, for example 2 minutes, 5 minutes, 40 seconds etc.
This 1 to 10 minute timer circuit when used along with a 7 segment display circuit as illustrated below could consume around 60mA current so probably a ac/dc adapter would be more preferable than a battery.
Circuit Diagram
Adding a 7 segment display to the above circuit
A simple pulse counter circuit using the IC 4033 shown below can be used with the above circuit for displaying the elapsed minutes.
The clock IN pin should be connected with pin3 of IC 4060.
The circuit will faithfully display the elapsed time in minutes right from 1 to the last selected minute output.
PCB Layout
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Sameer Patel says
Dear sir,
I have a light chaser machine I need a time interval of 20 sec between every bulb so pls help…. I have a local market chaser mchine…pls help with a diagram
Swagatam says
Dear Sameer, you will need to open the unit and locate the oscillator stage and then adjust the values of the relevant RC components for achieving the delay….if you could show me the internal snapshot I would be able to probably help you out…
Sameer Patel says
I wll help out with image
Sameer Patel says
Sir i m not able to upload image here …so any other way to send image to you..
Sameer Patel says
Dear Sir,
for images pls find the below link
https://drive.google.com/open?id=0B6nYqoqIyNBscGltSmpNeDhCQUU
https://drive.google.com/open?id=0B6nYqoqIyNBsUjBUZFgtakZfamc
https://drive.google.com/open?id=0B6nYqoqIyNBsZ2lNRWVjTjhDUWM
Swagatam says
Dear Sameer, it seems you did not tick the "share" option, therefore the images are not opening for me….please make it public and tick the "share" box
Ilman Gumilar says
Dear Guru,
If Guru has already circuit and the code, please send me by e-mail ?
Many Thanks and Regards,
ilman.gumilar@gmail.com
Swagatam says
sorry Gumilar, i do not have the code right now, if i get it will surely let you know.
Anonymous says
hi great guru, my name is timothy a finial year student do my project please am going to need ur help to design a circuit with a timer that can close a relay for 8sec and delay for 1hour contiuiously for 12hours then stop.
Swagatam says
Make the circuit that's shown in this article:
https://homemade-circuits.com/2012/04/how-to-make-simple-programmable-timer.html
this becomes your 8sec/1 hr timer.
once you do it successfully next we'll proceed with the 12hr timer integration.
Anonymous says
nice
Ilman Gumilar says
Dear Guru,
Can we make it by Arduino Uno ?
Thanks,
Gumilar
Swagatam says
Dear Illman,
yes it can be used.
Ilman Gumilar says
Dear Guru,
1. Can we set the duration of the Hours : Minutes : Seconds => 0 to 9h : 0 to 59m : 0 to 59s -> flexibly by using the up and down keys and display on 7 segment display as the duration of the timer ?
2. Having determined the duration of the timer can be made button start / stop ?
3. If the start button is pressed, the display will count down to 00:00:00 ?
Thanks,
Gumilar
Swagatam says
Dear Gumilar, it could be done but the circuit will involve many ICs and a relatively complex circuitry.