Here's the PIC controller for the Minisumo . As you can see it's pretty compact measuring 1" x 2.14". The PIC16F876 is hiding under the crystal. There are a couple glue chips for I/O, a 754410 Hbridge and a LM2940 LDO regulator. I left the header pins off to save space for mounting on the mini. Programming will be done thru the narrow 5 pin ISP header just left of the crystal, or through the serial port using a bootloader.
Eagle schematic of the 16F876 controller. Click for larger image. These are the side IR sensor boards I'll be using on the mini sumo. I'm gonna try a couple different IR LEDs to see if one is better than another. A couple I'm testing are side emiting so I went ahead and layed out a couple designs. They're using a Panasonic 4602 sensor. The trace around the detector is there in case I need to add a shield.
Here's a 555 timer variation of the IR detector I may try out.