ABS sensor technical specs?

[ideola]

On my 931 UWB project, I am installing rear trailing arms from an 89 944S2. They come with the toothed rear hubs and the associated ABS sensors. The display unit I plan to use is the Dash2 from Race Technology. It requires a wheel speed sensor that can provide a 5v or 12v square wave signal in order to provide speedometer and odometer function.

Just wondering if the 944 ABS sensor will work for this application, bearing in mind that I am also installing a completely custom wiring system, so I can provide either 5V or 12V to the sensor. Otherwise, I'll have to start looking for an aftermarket alternative.

[944 Ecology]

The S2 wheel speed sensor will generate a sine wave without other inputs. From peak to trough, it's probably 1.5 volts.

You should probably hook one up to an oscilloscope and see if it meets your needs.

[ideola]

OK, thanks for that.

[RC924]

Being an inductive VR (variable reluctance) sensor its output is not a pure sine wave and the P-P voltage will vary in amplitude with wheel speed. It is not difficult to convert its output to a 5V square wave.

Probably the easiest and also well proven circuit design is that of the MS VR zero crossing detector.



Quite easy to knock up on a proto board to interface between sensor and dash. You only need use one op amp, the upper one. Although both in the same IC, the lower circuit just gives an inverted output.

http://www.msextra.com/ms2extra/MS2-Extra_Ignition.htm#vr