Been in the UK I have to use the 2.4GHz xbee pro units rather than the 900MHz you folk in the US have access to. After a fair bit of playing and getting nowhere fast I added some buffering between the xbee and ardupilot. Using a 7404 chip I finally got reliable operations.
with the 7404 been an inverting buffer 4 are used (2 per channel)
Ardupilot Tx to pin 13, pin 12 - 11 and then pin 10 to xbee data in
Xbee data out to pin 1, pin 2 - 3 and then pin 4 to ardupilot Rx.
Pin 14 to +5v and pin 7 to ground. I put a .01uf cap across 1 and 7 for good measure.
Probably do the same with opto-isol but this worked well.
Hope this helps anyone else here in the UK stuck with the 2.4GHz version.
Richard
Replies
Hi,
My AP <--> XBee works fine without. Some sort of serial signal level conversion is needed between APM (5V level) and XBee (3.3V level); I was being a pig and just used series resistors. I have a home made "carrier" board under my XBee with a 3.3V supply regulator for it and the said resistors.
Maybe your "carrier" has a strangely designed level conversion and that may be why you had problems?
Regards
Soren