I've been researching using the AdaFruit VOC sensors w/ a MetaMotion and there are two versions. One that uses I2C which I posted a question on and the other that is simpler with a voltage read. I pretty much have it working.
However, to turn off the sensor you have to raise the enable PIN to 3V ish. That's fine. When I run my software to connect to the MetaMotion, the first thing I do is Raise DIO1 and the sensor turns off. When I need to get a reading, I lower DIO1 the sensor heats up and I take a reading, then Raise DIO1 up again to turn off.
That all works. However if I drain the battery of the MetaMotion and plug it back in to charge, it appears that since the DIO1 is low, the MetaMotion never gets enough juice to charge and actually boot.
So, the question is, what state are the DIOs in when the board boots? Low/High? Can that be defaulted to always High? Do some pins default Hi while others are Low?
I think I could change the MOSFET on the AdaFruit board to react differently.