New 10Ω resistor and thermal bonding cement means the chip acquires a stable 30°C in about 30s, with an ambient of about 18°C in the house.
40ºC took much more – 3 – 4 minutes, to be expected really, given the different between ambient and target is double, and the heatsinking is twice as efficent.
Still 30° will do nicely now until next summer, so the next job is to merge the code and move it and the hardware to Phoebe.
The general plan is that on startup, as soon as the MPU6050 is started, Phoebe loops until the sensor reads 30º using a rolling average to ensure it is really stable. At that point the code can be set free to run, and the temperature monitored at the same rate the ESCs are upted by PWM – about 40Hz.
Similar processing happens with calibration – sensors only take calibration readings at the point temperature has converged to 30ºC ±0.25%.
The underside of the breakout board is covered with 1mm foam tape so insulating it against heat dissipation, so about all I can to to make it better is to do the top also. A bit ugly so I’ll only do that if absolutely necessary.