Minutes of the PARTS meeting on April 27th, 2002 (May Meeting)

Pete Skeggs, PARTS President, opened the meeting by reminding everyone that the Seattle Robotics Society’s Robothon will be held next Saturday at the Seattle Center, and urged everyone to attend. He then reminded everyone that the PARTS PDXBOT.02 was scheduled for May 19th at the Smith Center Ballroom, and indicated that numerous positions still needed to be filled. He passed a signup sheet through the attendees, and described the positions that needed to be filled: line-following judge, floor exercise judge, set-up assistance, staging area, bullpen, backup scorekeeper, PARTS table, technology demonstration, people counters, cleanup.

Here’s the tentative event schedule, subject to change:

We had a discussion about the rules for line following. Pete explained that in both the beginner and advanced classes there will be two robots competing concurrently. Overall standings will be based on time alone; there will not be double-elimination, as in the sumo events. Attendees of the meeting agreed with this arrangement by a show of hands. The advanced line following course will differ from the beginner course in the following ways: 1) line width of 1/4-inch instead of 3/4-inch, 2) ramps, 3) sensors that lower gates that the robot must not touch, 4) line discontinuities, 5) variable line width, 6) lines that cross themselves. Larry indicated that unmodified Mark III robots probably would not be able to complete the advanced course.

• Warren Leach brought in the first batch of completed tee shirts for sale at only $15.00. The shirts will be sold for $20.00 following today’s meeting.
• Tim Rohaly reported that 125 Mark III robot kits had been sold (and about 100 kits shipped) so far. All unshipped kits are awaiting chassis and scoops. Sufficient electronic parts for an additional 100 robots have been kitted (again, except for chassis and scoops). Tim will have a stuffing party on Monday, April 29 at 7:30 pm at the Lucky Lab pub on SE Hawthorne to insert plastic into standoffs for all remaining kits. Kit prices will be increased after PDXBOT.02; kits will be sold at both Robothon and PDXBOT.02. There has been no further development on the assembly manual in the last 1-1/2 weeks. Ron Tsur volunteered to help Tim complete the manual.
• Matt Ivey reported that PDXBOT.02 press releases have been sent to local newspapers and broadcasters. Unfortunately, the press release that was sent to Computer Bits was misplaced; an announcement in Computer Bits will not appear in the May, 2002, issue. However, information about PDXBOT.02 does appear on the Computer Bits web site (www.computerbits.com). PDXBOT.02 will be covered during the May 18th Computer Bits Radio Hours, from 11am until 12pm on KBNP 1410AM. Matt also reported that Brett Nelson had done a great job of demonstrating his robots at the Benson High School Tech Night.
• Mark Gross brought his completed Mark III robot and his reference BASIC code.
• Eric Stewart brought a dual-motor gearbox from a Milton-Bradley Big Track toy. He had a 68HC11 processor and crystal and serial port chip for sale or trade. He showed some quality screwdrivers that he bought from Active Electronics. He showed some 200 rpm Maxxon gearhead motors that he got in a parts trade with a robot enthusiast in Italy. He also had his Turbot (described last month), some micro-sumo motors and recent catalogs. He is going to New Mexico for a Mark Tilden BEAM robotics workshop; everyone encouraged him to take plenty of photos and send emails to the PARTS newsgroup.
• John Hurley reported that he had taken his mini-sumo robot to Bill Harrison’s Northwest Robot Sumo Tournament last weekend. His robot would approach his opponent, but then would freeze. John won his second elimination round, though.
• Tim Brandon shared a photo of an asparagus-harvesting robot, and indicated that it could use differential GPS for control when prices drop a little more. He brought his Cyclops mini-sumo robot.
• Tim Rohaly reported that he became a GWS servo distributor in order to receive the lowest possible prices on servos. He showed a ball-bearing output pico servo for only $20.00. Tim won’t stock every servo in the GWS lineup, but will have a few. (More info about the GWS line of servos is available at www.grandwing.com).
• Steve Davee told about destroying the rechargeable cells of his micro-sumo robot when he accidentally reversed the polarity of his charger circuit. He also reported about a conference he attended where heart surgeons discussed the current state of the art in robotics heart surgery. One robot is actually capable of operating on a beating heart; the pencil-size hole and miniature pincers are much less invasive than stopping the heart. These robots use high frequency filtering to eliminate twitchiness, and motion scaling limits the maximum possible instrument movement. Future models will provide force feedback.
• Monty Goodson brought samples of Microchip TC44469 logic-input CMOS quad drivers. These were designed for driving MOSFETs, and can be used as direct small motor drivers (500 ma continuous total package dissipation). Data sheets can be downloaded from Microchip or from the PARTS web site.
• Mark Medonis reported that he is still cleaning out his garage. He brought in some PRESS-N-PEEL film for making printed circuit boards, and a copy of The Encyclopedia of Electronic Circuits. He has bought a CMUCAM from Ron Nucci that he will be adding to Maxwell, his robotic head. Maxwell will appear at the SRS Robothon and at PDXBOT.02.
• Alex Forenlich brought the mini-sumo robot he built in Brett Nelson’s robotics class at Saturday Academy. (Alex’s robot performed very well in the after-meeting competition.)
• Chris Viehoff brought in two Mark III robots; one was working, and the other one wasn’t. Chris wanted some feedback from other Mark III builders on possible solutions. He commented on the high quality of the Mark III kits, and said that they might be on the upper range of construction possibility for school-age kit builders.
• Larry Geib brought a copy of Robotics, Mechatronics and Artificial Intelligence (by Newton C. Braga, ISBN 0-7506-7389-3), a book that he recently bought at Powell’s Technical Bookstore. He also showed how a line-following surface could be made from white-surfaced melamine door skin and electrician’s tape (both available at Home Depot.)
• Tim Weaver described the various technical demonstrations that would be shown at PDXBOT.02: a Mark III robot disassembled but active to show how the sensors controlled the wheels, oscilloscopes showing PWM output for controlling servos and driving motors, Karl Kuchs’ robotic colony, Paul Burkey’s HERO-1, Warren Leach’s IR sensor wired to an LCD bargraph as a height sensor. Tim also showed his carbon-fiber mini-sumo chassis; he’s looking for surface-mount IR sensors for the sumo ring edge detectors.
• Eitan Tsur showed the RC platform he got from Larry Geib a couple of months ago; he has figured out the RC circuit works, and wants to interface it to a PIC chip. He’s learning assembly language programming so he can program his 877 PIC.
• Dana showed the latest refinements to his wheel tire mold. His son machined a custom wheel retaining screw. The next step will be to pour wheel treads around his aluminum wheels.
• Pete showed the sensor system he is building to control the gate obstacles for the advanced line following course. He is using modulated blue and green LEDs with collimating lenses with TAOS photo detectors. He also showed a quadrature encoder project he’s working on that uses Hamamatsu miniature photodetectors and an edge-triggered “D”-type flip-flop to decode speed and direction. Pete showed low-profile connector pins suitable for micro-sumo board interconnection. Pete’s micro-sumo robot was the only one registered in the micro-sumo class at Northwest Robot Sumo Tournament. Sadly, being the only registered entrant does not win the event.

The PDXBOT.02 robotics competition will be May 19, 2002 at the Smith Center Ballroom on the PSU campus.

The next PARTS meeting will be Saturday, June 1st.