Datalogging RPM signal

[Stephen Andersen]

Okay, I will reply to myself since after doing some research,
I am back to DIY mode.

The LabJack USB data acq unit DOES have a counter, but none of the 
canned software you get with it supports it at reasonable sample rates.

Someone had mentioned taking a square wave rpm signal, and turning it
into an analog voltage using an LM2917 or somesuch and some wiring.
Can anyone provide me with some insight (or preferably DETAILED instructions
;) on how to do this?

I will still need to do some programming to get maximum sample rate
on about 6 signals, but with the built in counter, I am limited to 
2 samples/sec which is not nearly adequate.  With the counter and custom
software I can probably get 16 samples/sec, but with the rpm as an analog
voltage I can get 25 samples/second with 6 channels...

Any input?  Offline is fine if no-one on the list is interested...

Thanks,
Steve

> Behalf Of Stephen Andersen
> Subject: RE: Datalogging RPM signal
> 
> Thanks for the pointer.  I am actually thinking about buying
> the USB logger board ($99) which has a built-in 32bit counter.
> I can snag the rpm signal to the DME in my car and multiply it 
> by 20 to get rpm (So I'm told).  I think with the 8 single
> ended inputs I can record enough (including the WB) for some
> decent tuning data...
> 
> Not exactly DIY though!!!
> 
> Thanks,
> Steve
> 
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