I have been running my GoPiGo3 for 45 hours over the prior 12 days, and just today saw my first
5v throttling event.
********* CARL Basic STATUS ***** 2018-09-07 10:44:46 up 25 min, 2 users, load average: 0.02, 0.07, 0.13 Battery Voltage: 9.21 5v Supply: 5.05 Estimated Life Remaining: 4 h 18 m Processor Temp: 49.4'C Clock Frequency: 1.20 GHz throttled=0x50000 Distance Sensor: 3.9 inches
I traced it to some executions of my center.py routine which centers both tilt and pan SG90 mini-servos. There is a possible overlap in the durations of re-positioning the servos, which apparently can cause the 5v supply to sag below the processor “low voltage” threshold.
Rotation spec on the SG90 mini-servo is 0.12s / 60 degrees, so I’m trying 0.2s delay.
With this delay, and both servos rotated 90 degrees from center, the rotation of the first servo has started, but not completed by the time the second servo is commanded to center. I am not seeing another 5v throttle event. Perhaps two “startup” current draws is too much, but one running and one starting is acceptable.