with the help of multiple erector sets, salvaged parts, and a few hours shopping, work on Ralph has begun! Ralph will be a multi-purpose robot, working toward filling simple needs. I also want Ralph to be a bit unique, so i am giving him two "brains" : 1 for the base (the part that creates mobility and simple object-avoidance) and a more powerful controller for the tower (arms, sight, speech(debatable), receiver, ect.).

my current peice of a project is building the base. a small, mediocre sketch is below.

the first part of this is somehow holding the peices in place. with my current lack of glue, i chose to use parts from erector sets (both old and new) to house the rear motor.

Sounds like a cool project; what are you going to use for a microcontroller? Is the project for anything in particular, or mainly for getting to learn more about robotics?

The first microcontroller is going to be an 08m2 PICAXE. other than direction, speed, and using the first rangefinder, it wont have to do much. also, when i begin work on the tower, this gets a line to that so the two microcontrollers can work together.

Bump:
im having trouble deciding the housing i would use for the battery. this is because im not sure whether i should keep the 3 AAs, or use a 9-volt. but the motor housing is finished, and im looking for where i put the wheels.

What's the supply voltage on that micro, 3.3V or 5V? And what's the rated voltage for your motors? I'd say that should dictate your power supply.

this comes from the Picaxe manual. however, i have read a tutorial book that says to use a 9 volt + some regulation or another.

Yes, you can use a voltage regulator like an LM317 to get 5V from 6-12V, for instance. Do your motors require a voltage higher than 4.5v?

not sure about that. the regular motor has used the 3 AAs with limited success (cant move well on carpet), but i dont know about the Servo.

Bump again:
Ive tested it out. the 9 volt works better. also, just to keep battery life going longer, ill be using 2 in parallel. i finished the motor housing, too. it doesn't swivel everywhere anymore.

@Kerm: because of your scouter project, you probably know tons more than i do for image recognision. how does that work/where could i find good documentation on this kind of stuff?

Since you're not going to want to spend months learning all the stochastics and advanced math behind it, take a look at OpenCV and its APIs and documentation. It makes things pretty easy.