Measuring PWM input signals

[virtuald]

Is there a way to read PWM input signals? We never got our FIRST provided accelerometer, and the one from last year works rather crappily... so we're experimenting with other ones. One I found has a PWM output signal, but I can't figure out what I should use to measure the signal appropriately. I have a feeling its in the counter object, but I'm not quite sure..

Thanks!

[nathanww]

You'll probably want to use an AnalogChannel of Accelerometer object. The counter is for monitoring digital inputs and when analog inputs cross a certain threshold. Since an accelerometer outputs an analog voltage relative to how much acceleration it's detecting, this wouldn't be that useful.

Also, make sure your electronics are competition legal--I know for a fact that last year's sensors are not, since they're custom parts.

[virtuald]

Its not the FIRST accelerometer -- its output is a PWM signal, not an analog voltage.

[virtuald]

Useful information in this thread: http://forums.usfirst.org/showthread.php?t=12086

[Nathan]

You could try adding a capacitor on the PWM signal line to act as a low-pass filter, and then run it into an analog input.

Or you could run the PWM signal into a digital input and use change notification (interrupt on logic level change). I did this to decode a PPM signal on a PIC micro and it works great.

Nathan

[Analog]

An RC lowpass filter may do the trick.