(Figured I'd append to this topic)
I've been working on controlling the AX-12 servos with Pololu's Wixel board. I've been combining my understanding gleaned from Webbotlib's libraries with the (relatively) standalong libraries written by a friend (github project here
). I've not fully succeeded in this, but that's besides the point.
The main thing that is done differently in the libraries linked is that instead of having one direction pin, routed to an inverter for the RX signal, two direction pins are used, thereby avoiding the need for an inverter.
What I'm wondering is: would it be possible to add an option in ProjectDesigner/WebbotLib for using two pins to send separate direction signals? This would reduce the circuitry needed. (and would allow both my Webbotlib boards and the Wixel to use the same interface boards, since I'm coding for the two-direction-pin approach)
Another observation that may be of interest: The Wixel is a 3.3V board, like the Axon Mote, for example. The 74HCN126 Tristate buffer powered with 5V does work with 3.3V signals to the buffer input. Thus, at most, a level shifter should only be needed for the TX/RX pins on the Axon Mote. I'm using the level converter from Sparkfun
with the Wixel.