M4 Speed Sensor

[senordos]

Hello,

The M4 speed sensor setup is via the digital input. I take this to mean that I need a switched high or low value (square wave) to trigger it. We're looking at hooking this up to the front wheel ABS system on our car which uses a hall effect sensor (magnet and teeth on cog).

Do I need something to convert what I imagine will be an analogue wave form rather than a square wave, or can the M4 be configured to use this as an input?

Many thanks!

EDIT: Apologies if my terminology here is incorrect. Further reading suggests that a hall type sensor WOULD give a square wave (although other reading suggest there are two types).

[AdamW]

A hall sensor is a DC square wave output, a VR sensor is the other common type and that is a AC, sine wave type output. You can often tell which you have by the number of wires, hall will typically be 3 wires, VR typically 2.
If you have a VR sensor you will have to use an external module to convert its output to square wave. Motec have the DMC, look at the bottom of this page: http://www.motec.com.au/sensors/crankcamspeed/
They are available from other vendors also, such as: http://www.vems.us/vr_to_hall or http://jbperf.com/dual_VR/v2_1.html
There are some OEM converters also such as vauxhall/Opel GM 09.185.826. See here: http://www.clubgti.com/showthread.php?2 ... ost2364070

[senordos]

Many thanks Adam. That makes a lot more sense.