Thanks! I am no longer with the research company that I was working for at the time I designed the board, however while I was there, we fabbed 45 boards (but only a subset of those were populated with components). I will enquire if any of…"
That was a hypothetical block diagram including all the optional parts of the system that were considered when designing the hardware. So we considered using altitude sensing using sonar, and designed the system so as to (hopefully)…"
""I got a kick out of the tilt sensor, a ball in a liquid which when tilted, closed a circuit by physical contact. I wonder if this would really work instead of expensive IMUs?"
Nope, it would work exactly the same as a 2-axis accelerometer with a…"
"Here is an open-hardware open-firmware board I designed to do servo switching (#3 in the article) in a failsafe way. It also can monitor battery levels or RF link status and switch based on that too. http://open.grcnz.com/trac/servo-switch/wiki