When I first apply power to my Raspberry Pi ( and Pi Droid Alpha ) the tilt and pan servos move about 15 degrees. After this initial movement, the servos are not active/powered.
I was starting my bot with:
center_servos()
servos_off() # no need to use a power holding the tilt/pan in the centered position
The servos_off() sets the servo pins from pwm mode to input mode,
BUT when I run the wheel motors, both servos go crazy to the end of travel and draw lots of juice.
If I leave the (SG90) servos in PWM mode after centering, they remain unphased by the motor commands,
and appear to be drawing less current than the variability in my ADC readings of the current.
Is this for real? I saw one post stating the resting draw was "< 10ma" so maybe.
Alan