Automated Backhoe by Roy Nelson legoroy@telus.net February 2006 The Automated Backhoe took 60 hours to build. Contruction/aquistion started in August 2005. It was first displayed at Supertrain 2006, Calgary, Alberta, Canada. It features the Lego Technic Backhoe #8455 automated using the Control Lab Interface. Programming done in Robolab. Features: Six motorized pneumatic switches control outriggers, shoulder rotate, shoulder lift, arm lift, bucket lift, and front bucket lift and dump. There are two style of switches, one style moves slower to control centering. Eight small compressor pumps arranged in a dual style configuration designed by Jennifer Clark in her JCB JS220 Excavator: http://www.telepresence.strath.ac.uk/jen/lego/jcb.htm Tread-link and chain-link conveyors to return black beans to pit. Four custom LED for headlights / tail-lights. Yes, I plan on using another LED for the dome light. Other LEDs indicate conveyor movement and switch movement. Comments: I wanted to be able to control the extension of the cylinders thus the slower motorized electric switches with touch sensors. Unfortunately the reaction time of control lab / robolab was too slow to stop the switch in the off/centered position. I then attempted to 'time' the switch back to the center postion. Unfortunately it seems that the CLI or Robolab occasionally goes 'stupid' or 'slow' so that the motors would turn on for several seconds longer that the programming specified causing eractic arm movement (switch moved to opposite open position). In the end I removed all attempts to center the switches. The backhoe ran for about 19 hours during the train show. After the first couple of hours a black beans caught between a gear and the chain-link causing the link to break. After a few modifications the backhoe ran for another 16 hours and only failed once. A bean jambed the conveyor but a little wiggling by hand fixed the problem. I am very pleased with the reliability of this machine. My previous long-running displayes (marble machines) typically failed every couple of hours. I decided to use black beans after estimated the cost of buying black/grey 1x1 round plate would exceed $30 USD. Total cost of black bean was $3, I could eat them, and I could care less if I lost some. Thanks to my uncle and aunt, Elden and Sarah for providing a cheap laptop and getting it too me just in time!