Build a pure slave transmitter?

[XarvoX]

Im trying to help my daughter (8 years) getting of the ground with her 3 channel e-starter-like trainer.

I bought her this package rtf, with transmitter and everything.
but its the cheap stuff, with 5 wires to servos, builtin speedcontroll and so on, but a 35mhz xstal on channel 70-something.


But my plan is to change her transmitter into a pure slave transmitter to my futaba ff9 (already got the trainer cable)
since her transmitter lacks trainer output this means some rebuilding of electronics..

So before i start jerking around with it, possibly breaking the damn thing i ask you guys, with the above known facts, can anyone estimate the type of job needed for this?

and what am i looking at?


im fairly good with a soldering iron, but i dont know much about transmitters..
But i do have breakout-specs for the futaba, so as long as i get the correct signal i can hook it up properly :)

[mmormota]

Building a ppm output to a radio is not too complicated.

Most transmitters built around a uC, and the ppm signal is available on one of it's pins. (check both sides of the pcb, sometimes the uC is on the bottom). You can find the ppm output pin using an oscilloscope. Even a free software oscilloscope (soundcard based) is perfect for the job:
http://zeitnitz.de/Christian/Scope/Scope_en.html

In order to protect the soundcard input, use a 100kOhm is series, and a 10kOhm parallel.

Just check the uC pins one by one. Once you found the ppm signal, solder a 10 kOhm in series and connect it to a Jack socket. Connect the gnd (battery minus) to the Jack as well.

Remove the quartz to stop the RF part.

The new output is working as a simulator cable connector as well.

The ppm signal (it's 5 ch, yours may have less or more pulses according to the actual channel number):

[Janusz]

Hi, http://www.rcgroups.com/forums/showthread.php?t=729269