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Old 04-01-2014, 02:04 AM
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mach4 mach4 is offline
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Quote:
Originally Posted by nr5p View Post
I have an 82 300sd with a non working tach amplifier. I've been wanting to practice with micro controllers for a while and figured I would make something useful with my arduino.

So what I am wanting to know is what type of signal drives the actual tach from the tach amp. Is it just a variable dc voltage and what is the range?
From what I've been able to determine the main sensor on the front pulley is a VR sensor that puts out an AC signal with variable voltage based primarily on speed, but also sensor gap. This signal is typically in the range of 10-11 volts. The tach amp changes the signal into a sine wave at 3.3 volts which is read by the tach module itself.

The later tach in the 85 for example, can be run with the VR signal driving the tach directly...not sure about the earlier ones.

Always interested to see what people are doing with Arduino. Here's mine - http://www.peachparts.com/shopforum/diesel-discussion/350205-engine-instrumentation-project.html

Make sure you keep us appraised on the projects progress.
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