Software Dyno...

[CSH-HQ]

Some early ratty testing I did, was just feeding into a comparator.
LM339, I think it was.  Just say away drom Op-Amp
Bruce


>Here's how we used to get wheels speeds from competitors ABS systems.  Tap 
>into the wheel speed signal at the ABS controller.  Note use twisted pair 
>wiring with a grounded shield, do not route near spark plug wires or similar 
>noise sources.  The consequence of noise on wheel speeds can be no brakes.   
>Just use an off the shelf F to V converter (frequency to voltage) and feed 
>the resulting analog signal into something that can use to record the signal 
>versus time.  Calibrate a voltage to speed conversion using steady speed and 
>some reliable speed measurement device(speedo?).  Note use an undriven wheel 
>and the signal will be extremely accurate as there are usually something 
>like 50 teeth on a speed ring.  Note your wheel speed tap may put noise on 
>the speed signal if you do not match the polarity of the F to V and the ABS 
>controller.  Also the newer ABS systems have quite sophisticated wheel speed 
>diagnostic circuits and may disable ABS once the F to V is hooked up.  We 
>used to buffer the signal, but I am unsure of the circuitry.
>
>
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