ChiBots Meeting Minutes – Sunday, April 11, 2010
The meeting was called to order by our President, Salvador G at 1310. All of the officers, plus the Program and Competition Chairmen were present. The meeting proceeded as usual, approximately following the posted agenda. The turnout of under 15 was less than that of our previous meeting. We were notified in March that the room we were promised at the library would not be available due to National Library Week activities taking precedence. Of necessity we moved the meeting to a “secret” location. Thank you, Dave J.
Our Treasurer, Tony S, gave his report. There were no expenditures for the month. Dues have been collected from 16 members since January 1, 2010. As noted in our previous minutes, the sign-in sheet now indicates paid up dues, since only those members are eligible for a door prize drawing. Don and Royce have still not been paid, but this is only because they have not yet turned in their expenses.
Al S reported results from a survey form which members filled out describing their interests, as well as presentations that they could give. Interests included: robot kits, miniSumo, RoboMagellan, walkers, BoeBot, VEX, 3pi and line following. Input was requested regarding all types of robots. AVR MCUs received the most interest, as both a 4K BASCOM and a C compiler are free. Also. AVRs may offer some technical advantages. Topics included control of PMDC, stepper and BLDC motors, as well as I/O expansion and a review of sensors (including MEMs) and their applications. Several members volunteered to do presentations later in the year.
Salvador reported on progress being made in the development of a new tri-fold. A draft is now on the ChiBots website. Members are invited to comment on the draft before a final version is printed. It is likely that the RoboMagellan picture will be updated, and another game will be added to the “short list”.
Tony reported on progress being made re Triton College. He has met with Antigone, and will contact Angel Guma, the director of Triton’s Trionics Club, which meets at 2000 on Thursday evenings. The shop area is not available on Fridays or weekends over the summer. ChiBots may soon be able to hold RBDOs on a monthly basis at Triton. If so, then we can offer to give robotic presentations and demonstrations for student members of the Trionics Club, and could also provide mentoring (when requested) for student projects.
Salvador reminded the group that our SRS RoboMagellan competition is scheduled for July 24th at the Moraine Valley Community College, with a backup date of July 17th. Per KJohn, these dates have been confirmed by the Dean, but the MVCC board has yet to give final approval. In the past we have had people from MN, WI and IN participate. Per our group email, someone from SW Ontario is also planning to attend. Hopefully, folks from IL will not be outnumbered this time.
Salvador announced that the Embedded Systems Conference is coming to the Rosemont Convention Center on June 7-9, at the same time that the Sensors Expo will be there. Registering for the exhibits (free) for either conference gives access to both exhibit halls. However, other than the free, 0900 Tuesday keynote address, one cannot attend the actual conference sessions of either group without paying a substantial fee. While the Sensors Expo tends to appear in Rosemont in early June every year, the Embedded Systems Conference moves around the country, and is unlikely to return for many years. There will be numerous papers, workshops and conferences presented at ESC that have a direct bearing on robotics. Parking at the Center is $13/car.
Salvador also mentioned Don K’s hexacopter group email posting (copied to the ChiBots website), as well as the postings by and about Mike Davey and his Turing Machine. Al S said that Mike has confirmed that he will attend the May meeting, and will do a presentation and demo of his Turing Machine. Mike attempted to closely follow Alan Turning’s 1937 theoretical description (see < www.aturingmachine.com/ >). With one exception (he couldn’t find a tape of infinite length, but did he really look everywhere?) his machine seems to be exactly what Turing described 73 years ago. If so, it is the first time that this has been accomplished in the hobby world.
One skeptic noted that Mike has a Parallax Propeller processor ’hiding’ in the console, which would, in his estimation, nullify the entire apparatus. This indeed might by the case if the MCU were being used for calculations. However, the MCU only controls the Machine’s mechanical aspects, runs a display and allows ready user access to several of the built-in features. Granted, Turing did not describe how the mechanical elements of his Machine were to be controlled, but then his knowledge of microcontrollers in 1937 was very limited (hey, you can’t know everything!). Mike plans to demo the subtraction of two, 2-bit numbers. If time permits, he will also show how his Turing Machine can multiply an 8-bit (Modulo 2) number by a 4-bit number. The results of that computation should be available sometime before Thanksgiving of 2014, depending upon how many hours a day the machine is allowed to operate. It runs somewhat slower than a 2 GHz P4.
Salvador, standing in for the Presentation Committee Chairman, introduced Al Schilling and his talk/demo entitled, “Handyman Robot Chassis”. Al started out by covering a variety of materials that can be used in hobby robotics. He had prepared several panels upon which were mounted examples of materials that can be used in the construction of robots. The first panel addressed wood, with examples of softwood and hardwood. Al described the uses of each, as well as their relative merits, shortcomings and sources.
The next panel showed several different types of plastic that can be used for robot building. The plastic can be rigid, or flexible, and colored, opaque or clear. Different tools may be needed for some of the operations, although wood-working tools can usually be used. Certain plastics tend to melt when machined, or may chip and shatter. A variety of techniques are often required. Sources were also discussed.
The last panel illustrated various metals that can be used. Titanium was conspicuously absent, but few members are currently building combat robots. Al presented the principle characteristics of aluminum, copper, brass and steel. Of course, entire books have been written on the machining and joining of each of these metals. Therefore, our discussion was limited by time to an overview.
The subject of hardware suitable for building hobby robots was covered at some length. Al then guided the discussion to suitable tools and how they are to be used. Both hand tools and power tools were covered, and a variety of tools were shown, including an array of “special tools” that have been repurposed from various fields to become useful in robotics, and in other endeavors that involve model making. As the group was relatively small and closely gathered around the presenter, there was a lively discussion, with the introduction of several additional concepts. Favorite tools were mentioned, including the “third hand”, the razor saw and a clip-on magnifier for glasses. The latter is especially useful when soldering SMT parts, or when ‘old(er) folks’ just need a little something extra.
Al presented and discussed various aspects of Design, Component Layout and the Building Process. He noted the merits of a common hobby adhesive, E-6000, which can be used for mounting many different components. Hot glue is to be avoided for final construction, as it has an unpleasant habit of ‘letting go’ at just the wrong time. However, it is suitable for rapid prototyping, where frequent changes are the norm. Finally, a number of parts suppliers were discussed. It is beyond the scope of this account to list all of the useful hints and tips that were conveyed during Al’s presentation, or in his handout. You need to have been there.
Al ended his presentation by showing several robots that he had built over the years. The first one did not have a microcontroller (MCU). Instead, it connected line following sensors to comparators, which in turn operated relays. The relays served as switches to turn the motors on and off. The second robot sported a BASIC Stamp on its own carrier board. It had a sensor package hanging down in the front which incorporated its own roller ball. This serves to keep the sensors at a constant distance from the floor. Al’s third robot featured stacked circuit boards, sensor arrays front and back, and wheels centered along each side. It was designed to compete in Line Maze, and is able to back away from a dead end without needing to first turn around. The sensors are supported by half of a chair glide, thus maintaining a constant spacing from the floor, as well as providing a gliding action at each end of the robot to aid differential steering.
Show, Tell and Ask was unusual for its variety. Terry showed a work in progress that had a simple wooden chassis, and featured an ingenious method of holding batteries of an unusual size. All of its electronics shared a small perfboard with the sensors. Several of the line following robots displayed their prowess in line following, using a portable layout brought in by Terry. Our host, Dave J, shared a variety of his things robotic, as well as the entire seven-volume set of “Build Your Own Metal Working Shop from Scrap”. This book series is available from < www.gingerybooks.com >. Mike Davey followed the instructions in these books to build his own forge and cast parts for his home-built lathe. Dave passed around his robots, including a Rug Warrior, SumoBot, AVR CamBot and his RoboMagellan entry (under construction) that features a 32-bit AVR on its demo board, complete with a Linux OS and an SD memory card. Door prizes were won by Noemi G (a MaxBotix sensor) and Victor D (a book). We closed on that positive note, and the attendees happily disbursed across Chicagoland, after first marking their calendars for the next meeting on May 16th.