Because all robot kits cost enormous amounts of money I started to develop cheap and small robot – Kobold.
Small because smaller components are cheaper, sensors with small range are cheaper and so on. I tried to get the robot about 40% cheap and 60% small. The goal size is nano sumo size – 25mm x 25mm x 25mm. The absolute maximum cost is set on €30 per robot, the versions developed now cost about €15 to €20 each. All parts are from ebay and local electronics store. Only custom made part is circuit board.
Later I found out about swarmbot Formica what seems to deliver same thing I’m trying to achieve. The problems in here are weird microcontroller (MSP430) and too weak mechanics. I’m using Atmel 8bit Atmega88, because it is one of the most widespread MCUs. Also servos for motors. I chose servos because they are cheap, strong and come with their own controller.