Interfacing an android device directly with an microcontroller in host mode

Question

Im doing a spy robot project with android. Im still in the planning stage.I need some help in controlling my bot. I need to connect an android phone to a micro-controller(say 8051) via usb then the MC via a relay circuit controls the robot. I know people use IOIO and ADK to interface a MC to android platform. But I dont need such heavy communication. Just 2 bits to move the robot motors.

I know there is enough support in android to communicate by usb. Im planning to use host mode so that i can also power the MC.I wanna know if it is possible to make such a communication directly without arduinos and IOIOs. If possible what do i program in the MC so that my app in android can detect it as a USB device and send data to it.

Also is it possible to simply convert the serial message to parallel from usb and directly use the bits to control the robot just by the relay mechanisms without the microcontroller. As the MC is really of not mush use but for serial to parallel conversion. I dont have any processing of data taking place in the MC thats why.

Answer 1

If you have access to USB on the phone and it can run a serial port profile (SPP), just connect up an FTDI to the 8051's UART and send information as if you were using a good old fashioned serial port (which, on the microprocessor is exactly what you would be doing).

The FT232R will be perfect.

IF you have a choice though, I'd use an AVR - assuming you need a simple eight bit processor - rather than an 8051.