- as it turns out you need dc blocking caps at every op-amp stage, especially the last one. AD5220 B lead cut, 0.1 uF added in series.
- the mega32 has no agnd, just gnd, and they are connected. so not connecting them externally does not help a lot.
- 0.1uF vcc filter caps are always a good idea around servos
- an avcc isolation inductor goes a long way helping ignore the outside world
- switching the AD5220 gain during receive seems to cause big problems. no idea why.
At right, photograph evidence that the sonar sort of works. Also, it can now drive around and avoid running into things. Large flat things anyway.
