My LEGO Robotics Creations
Welcome Creations Sets Books Competitions Links About me	The Grabber Arm This grabber arm is based on the "Master Builders Grabber Arm", which I first buildt from the step-by-step instructions found at the Lego Mindstorms pages. To my big disappointment the grabber arm was a machine with controls operated by a human, i.e. no need for the RCX. So, I used my own control instead: After letting the arm rest for about half a year, I got inspired to turn it into some kind of robot. I turned the RCX 90 degrees and placed the whole thing on a stand with a motor making it able to twist around. The RCX is used as an IR beamer, and a light sensor detects the reflections. Two touch sensors keep track of the arm, when it is in the upright position and when it is time to close or open the grab. A simple NQC program makes the robot turn clockwise until it detects the standing plate in front. Then the arm is lowered, it picks up the standing plate, turns a bit anticlockwise and puts the plate down again.
Thomas Waadeland / thomasw@ifi.uio.no / 011120