I just found this excellent Arduino hardware platform a while a go. Now I’m building my first project with it and have following idea.
I have Arduino Mega ADK, which acts as the main board for my application. It will be working normally as standalone with car battery as power supply, but to have control over the system outdoors-in-the-field, I need to make also portable device based on another Arduino and LCD. I would like this device to be without own power source and therefore I’m thinking to power it from the main board over USB.
I know that if I follow USB protocol and create for example a HID device, I can achieve this. Commands that I’m going to use are pretty simple and because of that implementing USB HID protocol seems like an overkill (haven’t studied that yet, so I don’t know how difficult that is using existing libraries). I would be happy with plain serial communication using my own commands.
Now, my question is… What are my options to achieve simple serial communication using standard USB cable connected between Arduino Mega ADK (USB Host connector) and another Arduino board (only available USB slave connector)? I would like to use existing libraries as much as possible.