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3 Minute Timer


jimcorrigans
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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

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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

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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
;)

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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

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