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davchar · 09-21-2008, 08:16 AM

Hi,
Unfortunately the voltage produced by the speedometer output was not sufficient to trigger the transistor. I did some probing and found out that the output was at ground between pulses. I then found a web page that detailed how to use a transistor as a ground triggered switch (Using Transistors As Switches). Using this circuit I have been able to get the MPGuino to read pulses from my speedometer output.

I have done some preliminary calibration and it seems about 2500 pulses/kilometre works well.

Now to get some fuel usage information!

Cheers,
David

09-21-2008, 08:16 AM	#6 (permalink)
davchar EcoModding Lurker Join Date: Aug 2008 Location: Melbourne, Australia Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts	Success Hi, Unfortunately the voltage produced by the speedometer output was not sufficient to trigger the transistor. I did some probing and found out that the output was at ground between pulses. I then found a web page that detailed how to use a transistor as a ground triggered switch (Using Transistors As Switches). Using this circuit I have been able to get the MPGuino to read pulses from my speedometer output. I have done some preliminary calibration and it seems about 2500 pulses/kilometre works well. Now to get some fuel usage information! Cheers, David