If you're using the UAV DevBoard with Futaba equipment or any other modern RC gear that outputs servo voltage of less than 3v, you're going to need a servo amplifier (also known as a booster or buffer) so the autopilot can reliably read your signals.
You can buy one from a commercial supplier like FMA for $15
, or you can use our dual optocoupler
and save yourself $10 for each pair of servos you amplify.
Out of the box, our optocouplers are designed just to clean up the RC signal, which is handy if you've got RF noise messing with your RC system. But if you solder two rails on the board (shown below), they become a very effective two-channel servo amplifier.
Make sure that the "input" side goes to the RC receiver and the "output" side goes to the servos or UAV DevBoard, like this (servo option shown):
When you're done, the servo amplifiers will take any input voltage and output a healthy 4.8v. Here's my scope data, from a Futaba FASST 2.4 Ghz system.