Crank / Cam VR Signal Generator

Free Open Source Hardware discussion forum. Post your Free Open Source hardware projects here!
Post Reply
TonyS
LQFP112 - Up with the play
Posts: 192
Joined: Mon Jun 21, 2010 4:18 pm

Crank / Cam VR Signal Generator

Post by TonyS »

I would like to make a Crank / Cam signal generator to feed the VR inputs of an ECM. The crank pattern is 60 - 2, and the cam signal is either 1 or 7 pulses per 720 degrees of crank rotation (job related).

I'm not looking to accurately simulate the behaviour of a VR sensor, I just want to generate a signal that the VR input on the ECM would be happy with.
A +/- 5V sine wave pattern is what I think would be appropriate / acceptable.

We already have a couple of in-house designed signal generators.
One is a bit old and "funky" (generates appropriate pattern of square waves with a PIC and then run it through some op-ampery to generate a trapezoidial looking, bi-polar signal). The other generates the signals by driving coils surrounding actual VR sensors, but the design files are lost.

My initial idea is to generate the signals by using a sine lookup table and an R2R topology on 8 output pins of a uC and then couple the signal to an audio differential line driver IC.

Any suggestions would be appreciated.
Thanks,
Huff
User avatar
Fred
Moderator
Posts: 15431
Joined: Tue Jan 15, 2008 2:31 pm
Location: Home sweet home!
Contact:

Re: Crank / Cam VR Signal Generator

Post by Fred »

Opamp + audio out + pc signal gen? that'll get your +/- signal. No real thoughts, keep us posted, though :-)
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!
Post Reply