The assembling instruction suggests keeping V_S switch connected to V+ (the out of the box option) if one uses NyBoard_V0_2 with plastic servos. But surprisingly it doesn't work to me. A calibration process goes well and the cat can go to the rest position, but any complex move like walking or even greeting leads to the sudden servos rotating on arbitrary angles in arbitrary directions. This in turn leads to the blocked servos, servos overheating and the cat crashing.
I checked #define NyBoard_V0_2 in Instinct.h, calibrated the cat and the accelerator few times, checked different potentiometer positions but it doesn't help. Only thing I did not try is replacing the bootloader. Without any hope I tried to switch SW3 and it seems to work. So I have two questions on this:
- Did I overlooked something? Is there any way to power the servos via the step down chip?
- V_S connected to BATT works but when cat is walking its limbs shake noticeably. I cannot notice such a shake during other moves (greeting for instance). Is it normal?
Thank you very much for fast response.
I was under impression that kit contains plastic servos but now I see that I was wrong about it. So V_S + BATT options should be ok for the kit.
Thank you for the great product :-)
When the cat moves abnormally, it indicates some instability in the signaling circuit.
There is some tricky output limit from the step down chip. It's not caused by average current, but some peak current. It could be caused by all servos moving at once, or a signal servo hitting a obstacle and drawing stall current.
Previously it takes very patient tunes to get it work properly, such as the output voltage, servo type, battery's discharging rate, etc. Connecting battery directly with servos seems to be simplest solution. The only concern is applying the raw voltage directly on none-kit plastic servos. Plastic servos usually have lower quality in both gears and circuits and fail pretty quickly, though the actual working voltage will be lowered by 1V~2V due to voltage drop on wires.
The cat performs motion just like a stop motion animation. The gaits are configured to have longer intervals and slower speed, so it's noticeable to see some shake. It's also caused by the control precision of the servos at certain scale.