NJDude -- thanks for the link! I think I read through that whole discussion,
and followed links to many others. That was quite an education. The term
"information overload" seems appropriate here.
This is what I've arrived at...
a) As designed/manufactured, OTG cables can not pass power through to the tablet.
Standard Android (as installed by manufacturers to their tablets and phones) does
not recognize an OTG cable plugged in to the usb port as a possible power source.
b) Modifications can be made to cables and Android to make this work.
- jumper a couple of pins at one end of the cable
- root the the device (tablet/phone)
- install a customised Android kernel to the device
There seems to be a whole cottage industry out there, aimed at customization.
Can you confirm my understanding? Have I missed anything?
I know that the Android world is about portability (thus battery-powered hardware),
but I hadn't realized the depths of that design philosophy. One of the side-effects
of portability is compactness. That's what drew me to the idea of using a tablet
as a data collection device (that, and b4a). Most new/newer tablets will use the
usb port for charging and external power, I don't imagine there are many that use
a separate power connection, like the Proscan. If my users were adventurous enough
to customize their tablets, they'd likely be writing their own software, as well.
It looks like I'm going to have to have a hard think about how far I want to go
down this path.
Thanks again,
John