insife FUTABA FC16 ? - Parallelport-PPM-Interface

[Alain]

I've a FUTABA FC16 radio with no trainer port ... Could somedy help me to find the location of the Rx signal inside the radio ?

PS : I'm not afraid to search it with an oscilloscope

thanks in advance

[johnhlong]

You need to find the series of pulses going from the controll section to the transmitter section. Use that as the output.

Then there is the signal level and polirity to figure out.

Would you like me to send you a picture of what the oscope picture should show?

John
Seattle, WA
USA

[Alain]

I've found a signal inside the radio and, yes, I would be interested to know if the signal looks like :
- pulses main frequency about 50 Hz
- amplitude : 4,7 V
- several pulses (one per chanel) inside the main period, the duration of the pulses is proportional to the sticks position
- reference is + 4,7 V, pulses are referenced to ground, when no more pulses the signal is high (4,7 V)

I am on the right way ?

Alain

[johnhlong]

Sounds like my older Futaba radio's signal train.

I connected that to the Parallel port and it worked on my Win95 machine.

When I tried to use it with my Joystick interface it didn't work. It turned out the signal was up-side down from normal. Since I have anothe transmitter that workd (It had a reversal switch) I haven't played any more with the Futaba radio.

I believe if I add one more transister stage to the interface )So it inverts the siginal) I think it should work.

What operating system do you use?

John
Seattle, WA
USA

[Alain]

John,

Up to now I've not tried to connect the Futaba to the PC. I think it will work since I'm under Win95.

When you used the Futaba, how did you manage to disconnect the RF part ? I've understood from the FMS manual that when the radio is equipped with a trainer port, it is possible to do it when connecting two pins together (3 + 5), but since I've no trainer port, I don't know how to do this with a FC16 ?

Alain

[johnhlong]

On mine I had to take the crystal out of the transmitter.

Mine had a board I could un-plug but when I did the interface stoped working, so the only answer was to remove the crystal.

John

[Alain]

Hi John,

Thanks for your answer. I've searched a lot on internet to see if the FC16 trainer module allows the deconnection of the RF part as the FMS users manual indicates (or seems to indicate for all Futaba radios ...)
In fact, it is now clear to me that there is no way to disconnect the RF part from an external signal sent to the trainers module. So I'll use your method : disconnecting the crystal !

thanks again

[Olivier Gibon]

Hy,

Check my website : the answer is there : you need the Ground and OUT signal as named in the site.
Olivier

[Sigge]