I’m using a Raspberry Pi 3 as the CPU in custom burn-in carts for cycling our Android tablets. It is hard to beat the 7” touch display using a Flask front end for quick development. The carts often have power connected and disconnected when moved around. We are also using a network inside of the carts for talking with tablets under test and need to bring this up each time we move carts and cycle power.
Before I get to deeply into specific functionality and operation of our charging carts, I thought it would be good to take a detour into drivers for custom hardware. In addition I’ll cover mocking hardware devices to allow testing of your drivers and operating your system in a simulation with no hardware present. This allows you to flush out your hardware design with software before fabricating PCBs. (A PCB takes a long time to “compile”.
Over the last 5 years, I’ve been working on a very small team as the sole Engineer designing a ruggedized Android tablet. The only product option that met our needs would cost 10 times what we could afford. These are to be produced and distributed free of charge in developing nations as a missionary tool. Due to the cost and effort involved in getting them in country, our goal was a tablet with a 10 year service life.