Speed Sensor Help

[UZZ30]

I have a dilemma with my UZZ32.

The original 4 speed had a bit of an issue from a coolant leak 10 years ago, seems it wasn't that well rebuilt. I had a spare A341E to replace it, however I felt that was a waste of time given the poor ratios.

I've since installed a 5 speed A650e and run it off a VVTi ECU which works quite well. Much more lively with 3.35:1 first gear rather than 2.5:1

Anyhow, this change meant I've lost the hall effect style speed sensor that runs 3 wires.

I suspected it would be an issue and sure enough the ECU and Dash no longer get a speed signal, which also feeds to the 4ws / A-sus / ABS / TRC computers.

The only speed sensor I can use is the two wire magnetic type on the rear of the gearbox.

The trouble is the 3 wire speed sensor made a square wave 5v signal, but this 2 wire type outputs an AC sine wave.

I need to somehow convert the 2 wire sensor feed from analogue to digital 5v and adjust the pulse rate so it outputs true to the ECU and Dash.

I have an Ardruino unit I might be able to use and code accordingly, but it seems like it might not be able to do it - not sure.

Anyone able to offer their advice on this?

Cheers

[sergei]

No need for arduino.

You need schmitt trigger. An opamp will do http://electronics.stackexchange.com/qu ... on-exactly.

Or actual schmitt trigger:
http://www.jaycar.co.nz/Active-Componen ... C/p/ZS5014

You can use optocoupler to isolate 5V input with 12V output.

Or even better you can use schmitt trigger optocoupler, something like H11LXM (eg H11L1M). Which is a 6 pin device:
https://www.fairchildsemi.com/datasheets/H1/H11L3M.pdf

Now the problem could be with how many pluses per turn your ECU expects vs how many does your magnetic sensor outputs.

[whynot]

I vaguely remember a problem like this on a stupid engine swap I did. you could use a single diode to generate a half wave pulse which might work. It will only cost a few cents to try it anyway. If the voltage from the sensor is not high enough then feed it through a small transformer. Try passive electronics first as its usually cheaper and less to go wrong and from my experience with ecus that age, they are not that fussy with the waveform as long as the voltage and frequency is right and not full of interference.