How to obtain PPM signal from RC receivers

How do I obtain the pure PPM signal from an RC receiver?

see this thread: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1199165055

see this thread: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1199165055

That’s great ,if one of the recevers shown is mine but mine is not illustrated.
Ted Rob

Ted, all PPM RC receivers for use with standard analog servos available today output similar pulses on the servo pins so the techniques discussed in that thread should work for yours. But just to be sure, what is the make and model of your receiver?

Ted, all PPM RC receivers for use with standard analog servos available today output similar pulses on the servo pins so the techniques discussed in that thread should work for yours. But just to be sure, what is the make and model of your receiver?

My receiver is schulze alpha 435 - I do not want the pulses to the servo pins but the pure PPM signal which will then be used by my processing board to operate my machine. At present the receiver fitted to the board is a Berg 72 MHZ RX and I bought a 72 MHZ TX from American Ebay to use it but the TX is faulty and cannot be used. I therefore have to use a 35 MHZ receiver (legal in UK) and I have this RX as described. Any of the receivers however seem very difficult to attach thev wire in the right place - so tiny.
Ted Rob

The Schulze uses a digital signal processor to manipulate the ppm signal, if you have an oscilloscope you may be able to find if there is a suitable ttl level output on one of the DSP pins. However, the chip is tiny and not easy to solder. One idea is to check if the PPM signal on each of the servo pins is output sequentially (as it would be in a non DSP receiver). If so, you could ‘or’ the 5 signal pins together to get your composite ppm signal.

Surely, all the latest RX’s use digital signal processing. I have no scope unfortunately so I cannot investigate that any further. What do you mean by “or” - I am not conversant with that shorthand.
I must put you in the picture about my problem - all I want is to operate my machine with my working 6 channel Tx ie Hitec Optic 6 on 35 MHZ and to do so I must feed my control board with the PPM signal - the board then sorting out the various channels from that signal. I admit that my knowledge of the finer workings of this and other electronic control mechanisms is to say the least very limited. I just want to operate my machine and at present I cannot. I saw a mention on this forum and thought that it could help.
Ted Rob (P.S. thank you for your patience with an electronic “thickie”)

I would guess that far more analog receivers are still sold than DSP at the moment.

For example, here is a page from a major UK supplier http://alshobbies.com/shop/cat.php?id=174&Desc=receiver&PHPSESSID=4a35be2027b237120b9fda31d84ad497

All of these popular receivers are analog. I would have recommended the Hitec HFS-05MS at £14.99 for a good low cost receiver or the Hitec Electron 6 as a good middle of the road receiver.

But you have the Schulze so lets see if you can get it to work.
One thing you can try is to connect the signal lines from all 5 channels to 5 digital inputs. If you can write a sketch that monitors each of the channels in turn you may be able to determine if the channels are output sequentially. You could start out just connecting the first two channels and use pulseIn to measure the pulse durations. By the way, if you have enough spare inputs, you could use this method and not bother reconstructing the composite frame.

If you are in the UK and somewhere near north London, send me a PM .