Follow on from: http://www.adamsinfo.com/linux-robot-watch-this-space/
I’ve been giving the layout and hardware of the device some thought. Hardware should be split up as follows:
At minimum, CPU, IO pin out, RAM, CF/SD, and USB controller. Wifi and/or ethernet would be nice. It will need to be linux friendly of course.
Custom IO board
Connect to Main board via 16 bit bus. The custom IO board will have some logic gate chips and maybe some memory. It will then connect child boards for LEDs, the ultrasonic sensors, switches and relays. The relays will then be connected to the wheels. I’ll consider adding other sensors for temperature, light, etc.
[ FILL IN INFO: I'm currently struggling to find a set of eyes for the device. It could contain some kind of laser scanner underneath which it can scan over the ground as it moves, trying to find something better and define a purpose for the eyes]
Each of the 4 wheels need to be at least 3 speed but 4 or 5 would be better.
[ FILL IN INFO: I need research and some good ideas on protocol and flow for the main board and custom IO board to communicate]
The wheels would ideally be ‘balls’ such as from mice. Need to research if this is practical/doable. For the battery, ideally it would be at least 6v and preferably 12 for the motors however this needs to be USB friendly and as such I’m considering a 4.2-4.7v Li-ION battery that will last a good few hours at full 350mA draw. Minimum might be around 180mA from initial research, but I may need more.
If I do need more which I’m considering a reasonable possibility, I might be able to step up 5v/60mA from the USB port to 12v/25mA and trickle charge an 11.2v battery. I don’t like the idea much though and the heavier the battery, the more power the device will end up using having to haul it around all day.
The radio at first was going to be an FM based setup. The USB base would contain a FM oscillator transmitter and the device would contain a receiver. It would use this receiver to locate the base station. I’m thinking that this is going to become a limitation and so I’m open to better ways of the devices maintaining simple communication.
The system will present all hardware inputs and outputs as available to software, including battery level.
All settings and fine tunes will be available on the device as variable resistors and can be hand tweaked. Ideally and in future, this would be software[automatic] controlled.
Short of a pair of wings or some kind of weapon, I think that’s about all the hardware we’ll need. I’m going to make sure that the IO card is mapped out in a way that allows for even more expansion. I will want to add an FM transmitter/receiver, some kind of sound device, possibly an LCD and definitely a camera and mic.
Thanks to Reader Phil, although I was looking at the beagleboard originally I’m thinking that this:
I’m sure that there’s more hardware out there but I’m having a hard time tracking it down.
The board isn’t available for order until the 13th October  so unless I can find anything more suitable, I’ll plan on working with this one.
At this point if anyone is interested in contribute any expertise or assistance, any extra help would be appreciated!
If anyone has any thoughts on this to now, please share in the forums
I’m going to keep researching boards but plan on using this one for the moment. I then need to start looking at the IO board and components.