MicroRAX Robot Chassis

The iRobot Roomba is a great robotic device for hardware hackers and robot builders.
They can be found on Ebay for as little as $20 with and without batteries. The battery pack seems to be the main reason they get sold because most users just don’t want to bother replacing the battery, which costs about $45 on Ebay. Other items that cause problems are dirty wheel sensors, a siezed cleaning brush motor and an occasional broken drive belt. Most of these problems aren’t a concern to hardware hackers.

This little four-wheeled robot has been through several changes during it’s life. It started out with a wooden chassis, then aluminum in a couple configurations and now here it is in it’s fourth iteration built with Micro RAX. MicroRAX are made from extruded aluminum and come with fasteners and pre-cut joinery hardware which makes them ideal for robot prototyping. They assemble quickly and accurately and can be easily reconfigured as the design may require. Prototyping is about problem solving and adapting new designs and MicroRAX make this easy!

This bot uses four Roomba motors, a Roomba 400 series mainboard and a Seeduino MCU. The Seeduino sends a PWM signal to the Roomba mainboard H-bridge to control the motors. The pictures below show the four points of motor control on the mainboard PCB. The yellow wire controls forward motion, the grey wire controls reverse motion. There are two H-bridges designed to run two motors, but each H-bridge can easily power two motors at once.

Get the code here: PING_sensor_obstacle_aviodance

Enjoy the build video and KEEP ON HACKIN!!