Author Topic: Adding a rev. counter to my engine tests  (Read 1741 times)

Offline geoff5269

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Adding a rev. counter to my engine tests
« on: March 12, 2015, 08:32:08 PM »
When I have finished my engines I like to test my engineering skills by seeing how slow or fast they will run, and how long they will run on one charge of air in my small compressor. After seeing another post here showing a cheap digital rev counter I thought I would add one to my test bed. I made a box for the display and a 9v battery and put a jack plug on the sensor wire and also made a holder for it. It does seem useful to monitor the speed so easily and any improvements made to the engine would show up in the speed available at a set air pressure. Here's a picture and a video.
Geoff

Offline b.lindsey

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Re: Adding a rev. counter to my engine tests
« Reply #1 on: March 12, 2015, 11:37:54 PM »
That's a nice little unit Geoff and I can see where it would be a very useful addition to the workbench. Do you have schematics for it?

Bill

Offline PStechPaul

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Re: Adding a rev. counter to my engine tests
« Reply #2 on: March 13, 2015, 06:49:38 AM »
Pretty nice! I made a tachometer using a PIC16F1825 that uses I2C to control a 16x2 LCD display. It's part of my TigTac (Transistor Ignition Tachometer) project that I'll bring to Cabin Fever. By then I also hope to have my air motor running and I'll add a proximity sensor to its flywheel as you have done. The sensor I have uses a tuned circuit and can detect any steel or iron - doesn't have to be a magnet.
 
It would also be informative to tally the total number of revolutions, which is what I thought you meant by a rev. counter.

Offline Ian S C

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Re: Adding a rev. counter to my engine tests
« Reply #3 on: March 13, 2015, 11:16:51 AM »
My methods of rev counting has evolved over the years, starting with a guess, it moved on to a 125 tooth gear driven by a worm, that served well for a number of years, I then got a bike computer that I could program for rpm, that was ok up to about 1000rpm.  I now have a non contact laser  tachometer, and I think that will do for me.
Ian S C

Offline geoff5269

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Re: Adding a rev. counter to my engine tests
« Reply #4 on: March 13, 2015, 12:11:39 PM »
Bill
Here is the schematic I used, hope this helps, I see I should have called this a tachometer.
I had fun testing the 2 Benson engines I have made finding one of them wouldn't go as fast as the other, then I realised why, one had a governor fitted and the other has not so it at least proves the governor works.
Geoff