RC servo to PIC controlled via RC transmitter

[Amoque]

The definitive servo control link: http://www.merlotti.com/EngHome/Comp...controller.pdf. This PDF explains mechanics, electronics, and control... with line by line description of how and what is happening and why. It goes over interrupts, serial input to controller from PC, and about every other thing you'd likely want to know. If you EVER intend to control a servo, I'd suggest downloading this 18 page, easy to follow, tutorial/ primer.

The author states the code is in Mikro-Pascal - and that may be, I don't know Pascal, but it is so close in appearance to PicBasic that I had to look twice...

[Scampy]

I'm confused.

You want to send a signal from an RC transmitter, to be received by an RC receiver, and then want to have a PIC connected to the receiver which then controls the servo ? why not just plug the servo directly into the receiver like a normal RC set up ?

If you want to drive a servo from a PIC, you need to generate a a pulse proportional signal between 1ms and 2ms refreshed every 50ms. If you could elaborate on what project you are working on and why you need a PIC between the receiver and servo it might help us to offer more suggestions

[Amoque]

Scampy, There are actually several reasons to do this.

While some newer transmitters have the ability to modify the servo response curve, older or simpler units require exactly this type of set-up. Suppose for example, rather than a linear response from the servo you require a logarithmic one? Or, rather than a smooth rotation, 10 discrete positions... with a microprocessor between the receiver and the servo virtually any response may be programmed to affect the servo - or servos. Really, nothing requires that the output be limited (or similar) to output to more than one servo. also, timing may be a reason - flip the stick to half... and the servo follows in a timed arc - "realistic" flying, where pilots try to mimic the look of real aircraft while flying is an aspect of this hobby many enjoy. I suspect that with proper timing and knowledge complex "3D" moves as well as many visual effects (lights, landing gear, bomb drops, camera activation) might be customized to the switches, sliders, and knobs on today's transmitters.

I have a pretty nice Futaba that limits the response of one servo based on the position of another - say, for example, to keep flaps from deploying at full speed or reducing control surface response at high throttle settings. Many of today's hi-tech models - from "Wings" to "V-tails" require complex control interaction to fly. And, of course there are any number of ground and water based models - and robots - that would only be possible with this type of control.

[Scampy]

That's interesting... thing is I have a 13 year old FM transmitter (old school given todays standards) and most of what you mentioned can be programmed into the transmitter, so the technology isn't that new.

I can see the logic though, you could have the PIC monitor the pulse width and if it's more than centre stick turn on lights etc.