Minutes of the PARTS meeting on July 6th, 2002
Pete Skeggs, PARTS President, opened the meeting by asking for a show of hands from first-time attendees; about ten people were attending their first PARTS meeting.
Pete announced that our hoped-for presentation by the Portland State Aerospace Society had to be postponed due to a re-scheduling of their next launch date. PSAS plans to launch its next rocket in August; work on the rocket prevented their representative from attending our meeting today. Pete said that we will include a link to the PSAS web site from the PARTS web site; one of the PSAS members told Pete that their rockets were the ultimate flying autonomous robots. Check out the PSAS site; they have some incredible multimedia videos of launches.
Pete announced that the Oregon Robotics Tournament and Outreach Program (ORTOP) has scheduled three First Lego League competitions this year in place of the single event held last December. There will be two regional playoff competitions: the first is for teams from Multnomah and Clackamas counties on December 7th at Wilsonville high school. The second playoff is for teams from Washington county on December 15th at Century high school in Hillsboro. The Oregon state tournament will be held January 18th at Clackamas high school. The competitions are designed for 9- to 14-year old students working as a team with LEGO Mindstorm robotics kits to traverse a standardized course and solve a set of problems along the way. ORTOP is looking for technical mentors for teams, and for volunteers to help run the competitions. More details about mentoring and volunteering are available at www.ortop.org.
Pete announced that he still had certificates of participation from PDXBOT.02 for those who haven’t picked theirs up yet.
Pete reminded everyone that PARTS is still accepting submissions of artwork for our club logo. Entries should be posted to the club file storage area at www.yahoogroups.com/group/parts.
Pete announced that PARTS now has about $1400 in the club treasury. Now that PDXBOT.02 is over, Dana will file the club’s application for tax-exempt status with the IRS (and send them a check to cover the application and filing cost). Despite the appearance of being flush, we’re still several hundred dollars below the minimum balance required to avoid having to pay monthly service charges fir the checking account.
- Alex Forenlich
opened the show and tell portion of the meeting by reporting that he had fried his 876 PIC chip while experimenting with his controller board. (This was on his mini-sumo robot he built at Brett Nelson’s Saturday Academy class.) Club members suggested he could get a replacement from Digi-Key, www.digi-key.com.
- Dan Gates announced that he had some Southern Oregon Robotics Club (SORC) tee shirts available for $20. He wanted everyone to be aware that the SORC club’s RoboMaxx exposition will be held October 12th and 13th. RoboMaxx will be a two-day event, and will feature mini-sumo, line following, maze transversal and open-class competitions. Entries in the open class may not be built from commercially-provided kits. RoboMaxx details are available at www.1sorc.com/robomaxx. Television station KTVL (Channel 10 in Medford, Grants Pass and Klamath Falls) will provide coverage of the event. Also, SORC club members and their robots will be the main attraction at KTVL-sponsored Kids’ Day on August 3rd at Hawthorne Park in Medford.
Dan showed a miniature retroreflective IR sensor that he scrounged from a junked VCR. He said that virtually all VCRs have these mounted near the take-up spindle, and the price is right. The sensor had wire leads, and is smaller than the Hamamatsu P5587 detector sold by Acroname, www.acroname.com/robotics/parts/R64-P5587.html.
Dan said that he has been working on adding a speech to Little Johnny. His circuit worked as a standalone prototype, but when moved to Little Johnny’s controller board, ran into interference from the controller’s clock.
Dan showed his line-following robot. It uses the Hamamatsu P5587 detectors to sense the line. Dan will eventually use the CMUCam for line detection, but hasn’t implemented that yet. He is using the Larry Barello controller board with Atmel AVR microprocessor, and is impressed with the speed that the program can be downloaded. Details are available at www.barello.net/.
Dan also showed the foam core that he will use as a layup core for his next-generation carbon fiber mini-sumo. He said that once the carbon fiber resin has cured, he’ll use a solvent (gasoline) to dissolve the foam and leave the body shell.
- Paul Burkey brought an article from Computer Bits about robot operating systems. Paul mentioned that there’s a reference in the article about the PINO open-source robotic platform. The article is available in the Computer Bits archives at www.computerbits.com/archive/2002/0600/robotos.html.
- Tim Ressel showed the beginnings of his mapping robot. It is built on a thick aluminum plate chassis, with large polyurethane skate wheels belt-driven by stepper motors. He’s using an HC-11 controller board he got from Circuit Cellar several years ago. He plans to mount a rotating platform on top for ultrasonic distance measuring. Tim mentioned a possible use for the robot: realtors could let it wander through a house, making measurements of room sizes and then calculating the actual square footage of the house.
- Karl Boe showed a couple of modules he had gotten from Kronos Robotics. The LCD Serial Backpack converts LCD displays to serial operation, and costs only $11.95. Details are available at www.kronosrobotics.com/detail.asp?product_id=LCDBP1. Kronos’ new Smart Module is a modular PIC microcontroller that permits a modular approach to building robotic controls or interfaces to LCD displays. Each module will have a library of basic functions, and all modules are serially-addressable on a daisy-chain connection. The introductory price for the Smart Module is $13.95 for the kit. Full details including projects, libraries and code samples (some of it written by Karl!) are available at www.kronosrobotics.com/products/smartmod1/smartmodov1.htm.
- Karl also brought business cards for the Metals Supermarket store near the airport, and shared some of his experience with slot-car motors, slot-car wheels and tires, and traction. He said that Raceway USA (a business Karl formerly owned) just west of Clackamas Town Center has Wizard high-performance motors and gear sets, and high-traction tires. He suggested using the lowest-profile wheels and tires possible, and said that masking tape can be used to remove dust and lint from tires immediately prior to competition. Raceway USA’s website is at www.racewayusa.com.
- Tim Brandon reported that following last month’s meeting he calculated Goliath’s coefficient of friction to be 1.32.
- Jon Bedson reported that lately he has been doing some vision research for future projects.
- Todd Reser showed a parallel-arm gripper that he had built for about $50. It used two straight gear racks driven by a single spur gear. Todd had mounted a gear-driven potentiometer for position feedback. He estimates that it would generate about fifty pounds of gripping force.
- John Hurley reported that he has been trying to design a motor controller circuit board that will use n-channel MOSFETs. He is using the free Eagle PCB layout software. He intends to use the driver board in a Japan-class sumo robot.
- Dale and Jana Hardin had surplus electronic equipment for sale. Periodically the school where Jana teaches replaces its lab gear. She raises money for additional equipment by cleaning, testing, and reselling the old equipment. She had 4 60-mHz LG oscilloscopes, 2 digital multimeters, and 1 signal generator for sale.
- Marty Fadness reported that he was going to attend a Microchip PIC class in Phoenix at the end of July.
- Monty Goodson reported that he was working on a very small pcb for a nano-sumo that he and Steve Davee are building. He showed a micro gearbox that he got for $3 from the same company that sells the gearhead motors used in Nemesis II. He got an evaluation kit at an Atmel seminar he attended recently, and wants to use the processor in a robot. It has 25 general-purpose registers instead of an accumulator, and no paging is required to access memory, so it should be easier to use than other microprocessors.
- Steve Davee brought his re-built micro-sumo robot. It is now faster and more powerful. He’s using Omron R2DG-41 gear drive motors from All Electronics. A connection diagram is available at www.allelectronics.com/spec/DCM-110.pdf.. He’s using toy Jelly Rings as tires. He showed the prototype nano-sumo that he and Monty are building. It will use four hearing aid batteries for power. He and Monty figure that since they’re developing the nano-sumo class, they will be able to establish the size and weight limits for entrants. Steve also brought a spring scale, some vinyl drafting erasers and a weight so club members could prove to themselves that increased tire surface area does not increase the force necessary to move an object.
- Someone (sorry, I could read your name tag!) wanted to run Sharp GP2D sensors from a higher voltage power source than was listed in the spec sheet. Members suggested using the forward voltage drops of several diodes to bring the sensor voltage down to an acceptable level.
- Warren Leach announced that he would moderate an HC-11 interest group. A separate yahoogroups newslist will be created to support this.
- Karl Kuchs said that he has been doing computer modifications lately and has not been working on his robotic colony. He reported that Dr. Marek Perkowski is on sabbatical for a year.
- Larry Geib brought sections of the line-following track so Dan Gates could try out his robot. He passed around the gearhead motor used in Nemesis II. He reported that he had found a BASIC87x interpreter for the PICmicro 16F876 and 16F877 PICs from Myke Predko. Details are available at www.myke.com/mbaspg1.htm.
- Daryl Sandberg described how he managed to buy both a milling machine and a lathe in one weekend. He said that Chinese-made machine tools should be considered “projects”, and he’s doing a teardown and rebuild of his now. He’d like to use four R/C car motors with gear boxes for his Japan-class sumo robot. He’s looking at equipment to make his own gears.
- Pete Skeggs described his experiences making encoders for motors. He’s using the Hamamatsu retroreflective detectors, and mounted his disk directly to the motor shaft for higher resolution. His first disk had stripes too narrow for reliable detection. He built a circuit board to decode the quadrature signal. His next version of the board will put the IC on the opposite side of the board to eliminate rubbing of the encoder disk on the chip, and he’ll re-orient the sensors He showed two books, “Sensors for Mobile Robotics” by H.R. Everrett, and “Behavior-Based Robotics” by Ronald C. Arkin.
The next PARTS meeting will be Saturday, August 3rd.
opened the show and tell portion of the meeting by reporting that he had fried his 876 PIC chip while experimenting with his controller board. (This was on his mini-sumo robot he built at Brett Nelson’s Saturday Academy class.) Club members suggested he could get a replacement from Digi-Key, www.digi-key.com.
It is built on a thick aluminum plate chassis, with large polyurethane skate wheels belt-driven by stepper motors. He’s using an HC-11 controller board he got from Circuit Cellar several years ago. He plans to mount a rotating platform on top for ultrasonic distance measuring. Tim mentioned a possible use for the robot: realtors could let it wander through a house, making measurements of room sizes and then calculating the actual square footage of the house.
The LCD Serial Backpack converts LCD displays to serial operation, and costs only $11.95. Details are available at www.kronosrobotics.com/detail.asp?product_id=LCDBP1. Kronos’ new Smart Module is a modular PIC microcontroller that permits a modular approach to building robotic controls or interfaces to LCD displays. Each module will have a library of basic functions, and all modules are serially-addressable on a daisy-chain connection. The introductory price for the Smart Module is $13.95 for the kit. Full details including projects, libraries and code samples (some of it written by Karl!) are available at www.kronosrobotics.com/products/smartmod1/smartmodov1.htm.
It used two straight gear racks driven by a single spur gear. Todd had mounted a gear-driven potentiometer for position feedback. He estimates that it would generate about fifty pounds of gripping force.
He showed a micro gearbox that he got for $3 from the same company that sells the gearhead motors used in Nemesis II. He got an evaluation kit at an Atmel seminar he attended recently, and wants to use the processor in a robot. It has 25 general-purpose registers instead of an accumulator, and no paging is required to access memory, so it should be easier to use than other microprocessors.
so club members could prove to themselves that increased tire surface area does not increase the force necessary to move an object.