Built to Spec

Well, I headed out to the Missouri State Fair Thursday, and you know what that means,

Food on sticks,

Chainsaw art,

And robots!  The Missouri 4H group set up an event called “Show Me Robots”  (http://mo4h.missouri.edu/events/fair/robots.htm) to show off robots in education in Missouri and what hobbyists in Missouri were working on.  There were a number of KC and St. Louis groups in attendance including a few FIRST teams, BEST teams, BotBall, MAKE: KC, ROBOMO, and Kansas City Space Pirates.   I was there helping with the Labywiinth display, sort of a joint project between the Kansas City Robotics Society and CCCKC.

For those that don’t know, the Labywiinth is basically a robotic Labyrinth game controlled with the Wii balance board.  I actually am a late comer to this project, which was spearheaded by Jestin (software) and Vince (hardware).  Eventually we’ll be building a 10’x12’ Labywiinth game for installation at Science City.  We brought our “medium” sized table (4’x4’) built by Rich and members of the Kansas City Robotics Society to the fair and set it up for people to play with.

I’m actually working on the motor controller hardware/software for the project that will allow an Arduino to easily control the actuator.  I’ve got a custom motor controller design lined out but I was only able to get one built before the fair came around, so I ended up grabbing 2 Parallax HB-25 motor controllers to drive the linear actuators.  The actuators used on the medium size table are two Firgelli Automations linear actuators with built in 10k potentiometers for position sensing.  The potentiometers allow us to do some interesting things with the actuators, like set them up with absolute positioning like standard hobby servos or auto leveling the table.  For now we’re just using them to set up some software limits (basically using the pots to mimic the functionality of physical limit switches in software) so we don’t over extend/retract  the actuators.

Check out this video of the medium demo platform in action as well as one of the smaller robotic labyrinths controlled with Processing as a demo Vince set up:

Unfortunately, one of our actuators died during the event.  It wasn’t completely unexpected since that platform’s been use for quite some time and the actuators extended beyond where they should more than a few times during debugging sessions and demos. Guess we’ll just have to start on the big one.