[Harm's] tumbling robot from a few years back is an excellent study in simple motion. Foregoing wheels or legs, he uses four flippers to roll the robot around the room. Two motors are used, each in charge of two flippers. Identical but separate circuits drive the motors with a 74HC240 gate IC monitoring the continuously rotation. When a flipper becomes stuck, the circuit reverses the rotation of the motor so the simple bot can tumble its way out of a jam.

The circuitry is less advanced than some of the BEAM builds we’ve seen before. That doesn’t diminish the cleverness of his design and we think BEAM robotics are great way to get your head out of the computer code and go hardware only. After the break you can take in some video of the  tumbling motion. We’ve also included a video of another bot from his website that uses concentric rings for another type of unique locomotion.

[Harm's] ‘W’ bot uses concentric rings for locomotion.

[Thanks Thomas]

The team from Tech-On has taken the time to teardown two interesting microprojectors. The first model they tackled was the Optoma PK101. It’s based around a digital micromirror device (DMD) like those used in DLP. Separate high intensity red, green, and blue LEDs provide the light source. A fly-eye style lens reduces variations between images. They noted that both the LEDs and processors were tied directly to the chassis to dissipate heat.

The next projector was the 3M Co MPro110. It uses Liquid Crystal on Silicon (LCoS) technology. The light source is a single bright white LED. The projector seems to have more provisions for getting rid of heat than the previous one. The most interesting part was the resin polarizing beam splitter. It not only reflected specific polarizations, but also adjust the aspect ratio.

[via Make]