Mayf;
F/V (frequency-to-voltage) converters would do the job of measuring
wheel speed but you should have as high a frequency as possible from the
wheel speed sensor so that the low-pass filter on its DC output will
have a reasonably fast response time. Otherwise you face a choice of
having fast response to changes in speed but with lots of ripple on the
DC output or with a longer filter time constant you have low ripple but
its response time will also be slow.
A way around that is to use a period measurement from the wheel sensor
and have a uP compare that time with the period of another wheel sensor.
The wheel speed data could then be logged, displayed, or both.
I couldn't read the schematic very well but I see that you will need an
op amp that has a common- mode range that goes to ground.
Regards, Neil Tucson, AZ
|