Homebuilt ROVs Forum

I've been reading how others have successfully used PPM from an RC radio down a single twisted pair to either a PPM to PWM converter or an RC receiver. I wondered if there might be some way of sending PPM directly from a laptop so I might have better control or more mixing options.

I'm brand new to PPM and RC radios so I'm not sure if this will work. Anyone know if this: http://www.endurance-rc.com/pctx.php on the topside would be able to connect to this: http://www.foxtechfpv.com/rmilec-signal ... -1342.html via a single twisted pair and work?

At a glance, the encoder and decoder look to be compatible, so I recon worth a try. A bench test will quickly prove whether they will work or not. For longer cable, and when running video in the adjacent twisted pair, if this is what you are planning, balanced transmitter and receiver should be used at respective ends to interface with the PPM units. Not doing this will result in reduced tether length capability and more importantly interference generated that will upset the video. Twisted pair is designed to be driven with a "balanced" signal; the PPM units are "unbalanced".
http://en.wikipedia.org/wiki/Balanced_line
RS-485 transceivers, or or RS-422 driver and receiver chips with the PPM units could be used to achieve this.
That aside, if you are up to writing the PC-side code then it would only be a small jump to program an Arduino or similar microcontroller board for each end instead of using the PPM units. That way you could use RS-485 and have bidirectional data (control down and compass and depth up) using a single pair.