Detecting bi-polar input using Arduino / MCU

[danners430]

Afternoon folks,

Yet another question regarding RC receivers, albeit loosely :-)

I've discovered that the RC receiver I'm using outputs a bipolar PWM signal depending on user input. If the joystick is moved "forwards", we get a positive voltage, and if it's moved "backwards" we get a negative voltage.

Since Arduinos and MCUs generally can't detect negative voltages, I thought of using a pair of optocouplers to detect the two signals - one for detecting the positive voltage, the other to detect the negative voltage. Does this sound like a reasonable solution?

Cheers

Daniel

[In Vacuo Veritas]

What receiver is this? This isn't like any RC radio I've ever heard of.

Why not just couple the signal to 1/2 the rail with a resistive network?

[Zero999]

What voltages do you expect from the negative PWM signal?

How about scaling the voltage to within the power supply rails of the MCU and using a comparator to detect the appropriate threshold voltage?

[mikerj]

Sounds like this receiver has a motor speed controller built in and the OP is looking at the voltage across the two outputs.  If so them measuring each output with respect to ground should give a unipolar PWM signal.

[danners430]

Hey guys,

Sorry for the lack of response, I was about as busy as could get yesterday [emoji23]

I've double checked with the manufacturer, and the info I was getting is wrong - it actually outputs a positive PWM signal, no negative voltages used... Problem solved by itself!

Cheers anyway folks!

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