We’re running the X2’s on our robot off of a 6V battery. Because voltage can drop under load, we want to try to isolate the logic power to avoid brownouts, possibly using a separate battery for the logic. We’ve identified 3 possible approaches… can you comment on if any is better than the others?
-
Wiring in regulated 5V power to the power/ground pins on the I/O block, as some have done before, and removing the power switch to avoid powering the onboard vreg. Pro: Easy to do. Con: Removes an I/O port. Somewhat easy to dislodge. Questionables: Will this damage the vreg? Are the traces able to handle the distribution (assuming we don’t do any high current tasks like running servos).
-
Wiring in regulated 5V power to the USB port, shorting the USB-VCC jumper on the bottom board, and removing the power switch as above. Pro: Harder to dislodge (we work with kids, so it’s nice to have), preserves the I/O port. Questionable: The USB-VCC trace is smaller; can it handle 500mA?
-
Clip the pins connecting VBat from the motor driver board to the bottom board, then wiring a separate connector using the V+/- holes at the top of the bottom board. Pro: Don’t need to regulate incoming power. Con: Hard to reverse. Questionable: Do those power pins serve other purposes?