Minutes of the PARTS meeting on June 7th, 2003

President Pete Skeggs opened the meeting by showing the intro that Shawn Marshall had created for a video he is producing for PDXBOT.03. Shawn later said that he used Lightwave to create the animation.

Treasurer Dana Weesner reported that PDXBOT.03 tee shirts are still available for $15.00, and that we’ll try to sell remaining tee shirts at the Beaverton Summerfest on July 19-20 and at the robotics competitions in Seattle and Grants Pass this fall. Over 700 raffle tickets were sold at PDXBot.03.

Pete said the he had gotten an inquiry from the organizers of the Beaverton Summerfest asking if PARTS would be interested in showing robots in the IBM Tech Pavilion tent. Pete said that ORTOP would have a display there, and asked for a volunteer to coordinate a display of PARTS robots. Tim Rohaly volunteered to coordinate; Pete will give contact information to Tim.

Pete encouraged all winners of PDXBOT.03 prizes to send an email thanking the donors. Pete won one of the Kronos Robotics DIOS Ultra development kits, and reported that it was fun to win something that he could start working with immediately.

Vice President Warren Leach reminded PARTS attendees of the garage sale at Prefix later in the day. He said the easiest way for most folks to get there would be to take the 207th exit off of I-84 eastbound to Start Street, then east to the Prefix office at 21640 SE Stark.

Secretary Doug Arnold reported that the PARTS membership list was getting really long due to inactive members. Anyone who has not attended a meeting within the last year will be dropped from the list. Pete asked that a separate "inactive" list be maintained.

Show and Tell started with Dana Weesner who showed an H-bridge motor driver board that he had built, along with two motors he intends to mount in the Japan-class robot he and his son David are building.

Daryl Sandberg showed a pair of paper feed rollers he snagged when the copier repairman fixed the copier where he works. He plans to use them on his next mini-sumo robot. He reported having bad luck with Infineon TLE5206 H-bridge motor drivers. He said that the Arrow Electronics folks have been pretty good about working with him to replace the defective parts. Daryl won the Solutions Cubed Easy Roller wheel kit, and passed it around so everyone could see the geared motor and wheel assembly. He passed around a pair of servos he had altered to permit back-to-back nesting for use in a mini-sumo robot. He reported that he and Tim Weaver are collaborating on an article that describes the design and construction of their robots, Goliath and Solo.

Tim Weaver reported that he’s re-writing the code for LandShark from C to assembler to make it more compact and faster.

Mark Medonis showed his Maxwell animatronic head at PDXBOT.03. He has created molds for a new .060" polycarbonate chin for Maxwell. Mark showed a bubble-filled vacuum-formed chin that resulted when water absorbed in the polycarbonate created small bubbles when heated. The solution is to dry the polycarbonate in the over with low heat prior to heating it for vacuum forming. Mark gets his polycarbonate from Multicraft Plastics. He said Multicraft has polycarbonate sheet as thin as .010", and has provided him with very quick service for on-demand cutting.

Karl Boe reported that he has gotten back to machining parts for Blockhead. He is using the Kronos Robotics DIOS Ultra controller, and said that a single power supply for both the controller and the motors has been problematic. Karl reported that the Kronos web site has been updated with an application note about how to avoid power problems.

Monty Goodson showed the microcontroller and line sensor circuit board kits he plans to sell. He uses these boards in "Mousetrap", his latest micro-sumo robot that employs a fold-up design and springs open into full size as soon as the robot moves. Monty’s sumo body is made of polycarbonate that Bruce Filener laser cut. Monty used solvent to bond the body parts. A thin elastic band helps to unfold the body, and neodymium magnets hold it in place once it has expanded. (Karl Boe suggested Radio Shack as local source of neodymium magnets; a package of two sells for $1.98.)

Steve Davee related the sad story of how his micro-sumo battery shorted out and created so much heat that it re-melted his hot-melt glue. He cautioned others to carefully inspect and route their battery wires.

Tim Rohaly reported that there is a new Basic Micro ATOM controller board designed for the Mk III mini-sumo robot. The ATOM is 100% code-compatible with the Parallax Basic Stamp. Tim also discussed his experiences working with the Motorola MC33794 E-Field evaluation module. While this device was supposed to remotely sense the presence of objects, Tim found that objects needed to be within a centimeter of the sensor wires to be detected. The requirement for a 12 volt power supply makes it impractical for small robotic applications. Tim recommended the QProx sensor (available from Digi-Key) as a better alternative.

Pete Skeggs showed the robots he took to his son’s second grade class. Pete’s line follower uses wheel encoders. "Trashbot" is built inside a small plastic trash can, and uses Delrin chain and drive sprockets purchased from Serv-O-Link. There are Sharp IR sensors on the underside of Trashbot’s hinged lid that scan horizontally and vertically. Trashbot will follow objects, and will back up if it gets too close. "Cloverbot" uses some parts saved from a robot that Pete built as a teenager. Cloverbot uses ultrasonic ranging, and has an SPI (serial) connection to an HC11 controller. Pete recently added some weights to keep Cloverbot’s "head" from bobbing. Pete uses a text-to-speech synthesizer utilizing an RS-232 interface from RCSystems in Seattle.

Paul Burkey showed a brochure for the new RoboMower RL-800. He said he buried a perimeter wire around his yard, and the mower will traverse a pattern within the wire. Paul hasn’t tried to hack his new lawn mower yet. He also passed around a Popular Science article about the new Honda and Sony bipedal robots available for purchase soon.

John Hurley reported that he got a CMUCam, and wants to try setting it up for line following.

Eric Stewart reported reading an article describing research at Washington State University on Palouse PiezoPower (P3) motors, the world’s smallest. He said that 6000 of them would fit on an 8-1/2x11 sheet of paper. They can also be used as small generators. Also, he had read about a prototype microfiber developed at Berkley that mimics the gecko’s foot pads, and thought it had potential for increasing traction of sumo tires.

Steven Minichiello showed the Lynxmotion L5 robotic arm kit he won at PDXBOT.03. He is modifying the gripper so it can be directly driven (instead of driven via acable). He said the software is good, but the mechanics of the gripper need work. He dressed all of his servo leads with adhesive Kapton tape.

Warren Leach reported that he wouldn’t be surprised to see an article about PDXBOT.03 in EETimes. Warren said the he was interviewed during the event by a writer from the magazine

The next PARTS monthly meeting is July 5 at 10:30 am in PCAT 28.