3 Minute Timer

[jimcorrigans]

I am trying to develop an invention that I have a real passion for but I need to make or buy a timer. Well its two timers really, the first one lights up after one minute and the second after an additional two minutes. Can any of you kind people point me in the right direction?
Kind Regards
Jim

[ante]

Hi Jim,

Welcome to our forum.

You have to reveal a little more about your invention so we are able to help you! What I mean is we need to know something about the voltages and how much power (Watts) you like to control.

[jimcorrigans]

Thank you for that warm welcome Ante. As a Gas Engineer I have to carry out Gas Pressure tests on a premise. The first part is to connect a U Gauge of water to the pipe work to be tested. I time this for one minute, if the water hasn’t gone up it means that the main inlet valve is not letting bye. Next I increase the pressure to a higher level and allow a further one minute for the temperature of the incoming gas levels off. I now read the level of the water in the U Gauge and wait for a further two minutes, if the level hasn’t dropped the pipe work is sound.
What I need is a timer, or probably two timer’s one for one minute and one for two minutes. At present we use a standard stop watch but this is another piece of kit to carry, as we usually work in dark places a timer with a green and red LED (start and stop) and a Beep would be so much better. It has to be compact to fit into the U Gauge and have an on/off switch. Unfortunately I am not very good at explaining things; I hope this gives you some idea. Any suggestions or ideas will be gratefully received.

Kind Regards

Jim

[ante]

Hi Jim,

So, we are talking battery powered and spark free!? ;D
I suggest a CD4060, LEDs, a piezo beeper a three way switch and a few small parts in a sealed box.

[gogo2520]

Hello jimcorrigans


Ante is right about using the CD4060 for a timmer chip, thats if you have at lest about a 12 Volt power supply handy. But it could been done with with a coupple of transistors and some caps, plus some resistors. Sounds like a new Project Thread to Me. I think this timmer could be run off of 1.5 volts or so.  Cool something to think about.  SMD's come to mind?
                                          Have fun
                                              gogo

[audioguru]

Ante is right about using the CD4060 for a timmer chip, thats if you have at lest about a 12 Volt power supply handy.

Why 12V? A CD4060 is an ordinary Cmos logic IC that works fine with a supply voltage down to 3.0V.
A high speed Cmos IC 74HC4060 works down to a supply voltage of only 2.0V.

[jimcorrigans]

Thank everyone for you

[gogo2520]

Hey audioguru
  when I think cmos I think 12 volts, old school.
                                            gogo


PS.  jim were not done till its over done

[audioguru]

Hey audioguru

[ante]

To power the timer a small PP-3 and a low drop regulator like L4940 or similar would be fine, this will keep the timer run exactly right each time.
Here are a few examples on CD4060 circuits, of which some are very well explained:
http://www.circuitsonline.net/circuits/view/106
http://www.doctronics.co.uk/gt_1.htm
http://uk.geocities.com/ronj_1217/al1/24t.html
http://www.hometoys.com/tips/tips18.htm
http://users.otenet.gr/~athsam/timer_with_buzzer_and_optocupler.htm
http://www.zen22142.zen.co.uk/Circuits/Timing/ivt.htm
http://www.ieee-rgit.com/viewproject.php?id=2&PHPSESSID=fab893c4e61ebfc9fec74a12f6fd5cba
;)

[jimcorrigans]

THANK YOU - THANK YOU - THANK YOU
I am going through those web sites you suggested and love every minute. They are brilliant, I wish I understood them a bit more, but with more years behind me than I have in front of me I do worry if I have time to learn all the things necessary to produce a finished item, so here I am, cap in hand, are there any kits around that can cut the learning curve?
With fingers crossed

Regards

Jim

[ante]

Hi Jim,

Your local electronics store might have a kit for you. Most simple timer kits use the 555 IC instead of the CD4060 which I prefer, but still it works as a timer.

[prateeksikka]

hi.
how about using a charging RC circuit so that capacitor voltage builds upto 0.7V in 3 mins .this can be fed to the base of a transistor and push it in saturation.
your views ????