What do I need?

Projects General Guidance
1

Please help. I'm not sure what I want is even possible. I'm looking for the smallest possible footprint that will support my needs. I outlined it like I did because I'm not sure if we talking about different configuration for V 1.0 from the everything V 1.3 configuration.

minimum requirements - V 1.0

  • To be able to interface with an Android phone via USB. all buttons and relays controlled by Android OS
  • 7 buttons, no two buttons will be pressed at the same time.
  • turn off/on 4 LCD's

V 1.1

  • powered via USB port from smart phone

V 1.2

  • can control 2 solid-state-relays

V 1.3

  • control output to a small LCD display

The questions is: What do I need to meet the MINIMUM and what would I need to meet ALL the requirments? Thanks.

2

You need USB Host capability to talk to an Android phone. A clone of the new Leonardo model on a custom board would get you that in the smallest footprint.

1.1 might be a problem since the phone generally ACCEPTS power from the host, not the other way around. You may be able to steal power from the data lines but that is not something I would expect.

1.2 should be no problem.

1.3 should be no problem, as long as you can find a serial LCD of the size you want.