RC signal decoding

tobdec

Hey everyone, first post and prob a noobish one too lol

I am in the process of building a rather large completly rc robot. I have a basic stamp 2 that I would like to decode the RC code from the receiver and then mix the channels to be output to my h-bridge's. How would I go about doing this? Sorry if this is common knowledge but I just cant seem to find a straight answer anywhere.

Thanks in advanced!

W9GFO

Look up the PULSIN and PULSOUT commands.

tobdec

Ok so I've been checking those out. If my understanding is correct the PULSIN command stores the length of the pulse? Meaning, not how often the pulse occurs but how long the pin is high?
I have the homework board and I remember the PULSOUT positioning servos by the duration. Modern RC receivers have outputs using PWM correct? Or is this PPM? Sorry for all the dumb questions

GordonMcComb

Some sources on the Interwebs very incorrectly state that servos are pulsed using PPM, but this is wrong.

If you want to call it anything, say that servos are controlled by pulse *duration* modulation. So, obviously, it's just the duration of the pulse that matters, not their period, position, or anything else.

R/C receivers haven't changed the format of the signal they produce in decades. It's still a stream of 1-2 millisecond pulses, spaced more or less 20 milliseconds apart.

-- Gordon

tobdec

ok ao basicly to decode this I will use the PULSIN to mix the channels and use PWM to drive my h-bridges. Im still a little new to pbasic, to make it realize that one pulse is shorter or longer than the other what aproaches could be used? When I save the PULSIN in a word variable will it simply be saved as a dec number?

tobdec

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