Jan, On 01/09/06, Jan-Erik Soderholm wrote: > > > erm, strange PWM as the period is at 50Hz > > (around 20ms) but the duty cycle is between 1-2ms. > > That is not strange at all, It's a plain standard RC-servo > signal !! I know, I know, I just meant that normally you would say Xms period and Y% duty cycle, so many times the duty cycle almost fills out the period -- but not with these servos (5-10% duty cycle). Yes, the "pulse", correct. The timing of the pulse lenght > is what's important. The 20 ms interval is not (as important). OK, but at least I thought that I can synchonize to the period and drop all signals that are out of synchron no matter the length is in between the valid range. But I was actually wrong on this: it is not just about the receiver, but also if I change other analog channles on th econtroller the period just a bit changes (but not as much as the duty cycle). That is enough to not to count on that, and of course the receiver also produces strange periods and loosing the syncron means loosing the control. Resynchronizing is very hard as out of synchron happens only when the noise is too much. And why do you think that it should ? The function of > the servo is not dependant on the intervall beeing > "exactly" 20 ms. It can probably be 15-25 ms without > a real problem. It would not be a problem as I thought I could measure the signals when switching on the device, so that the rest of the time I could measure that one. But it changes during the operation... Are you designing a "modell-saver" ? Yep, but not just a failsafe as there are many of them already, but a filter, so it supposed to work even in bad conditions -- you still will be able to control, not just put the device into a safe state. That latter one is the latest choice when the signal lost for a long time or the noise is as bad as there is no valuable signal for so long. > Interestingly when I switch off the thransmitter it knows > > trait away that there is no signal so shuts down the > > system after a couple of moments. > > What is "it" and "system" ? it = my little device system = device + servo (failsafe mode) The RC-receiver should see that there is no 27 (or 40) > Mhz carrier and stopp producing pulses on it''s servo > connectors. It that what you are saying ? Unfortunatly the receiver receives noise and treat that one as a valid signal. It is an analog receiver, so that it does not check if the signal is valid. It just demultiplexes tha channels and puts out the signals (duty cycles). So the receiver still produces pulses ? Funny... I was surprised too... Actually I have mad a good progress on that this evening using that WAV to Stimulus converter I have just wrote. Still have some issues, but now it is quite stable :-) Tamas -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist