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Meeting Report Tue 14th April 2009 |
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Written by RichardJones
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Wednesday, 15 April 2009 |
The evening was very well attended. We were pleased to welcome Kate Coleman with parents and youngsters from http://cagcy.org.nz as well as many of our regular attendees. The gold coin collection raised $82 for Science Alive which was very much appreciated. Thanks to all who came, especially our speakers John Wynyard and Charles Manning who put so much energy and preparation into their presentations. Meetings are now held on 3rd Tuesday of even numbered months. Next meeting will be on Tuesday June 16th 2009 in the Science Alive Seminar Room. Offers of presentations and topics for our next session most welcome. For those who were not able to make it, here is a record of what we did (do let me know if it needs updating) ...
John Wynyard from Science Alive gave us an introduction to Robocup Junior Rescue, Soccer, Dance and Theatre categories with live demonstrations of robots performing rescue and soccer challenges. The Robocup web site is due to be updated soon with new rules, application forms and venues. See: http://www.robocupjunior.org.nz for more details. John has an .avi movie on DVD available with scenes from the National Competition, this gives an idea of the standard required to get to national level. Our regional competition will be held at Selwyn House School on 9th August 2009. Stuart Whelan has offered to coordinate individuals, not associated with a school entry, into teams providing a venue, space, and technical assistance. Stuart may be contacted by email here:
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Alex brought along a new NXT sumo robot that had a very neat spiked roller to catch and pull the oponent off its wheels. It gave a very convincing demo of pushing my robot, Gnasher, out of the Sumo ring. Thanks Alex for bringing the robot and your Dad.
Peter showed more robots from the Robokits range including a tiny robot from Polulu with very smooth line following action. Peter has a huge range of NXT sensors in stock. See the whole lot at http://www.robokits.co.nz/
Matthew showed us an ingenious way to create a free running ball castor from a ball bearing held captive in a wooden frame with a nut and bolt to run in.
Timothy showed a line following robot made from Tamaya gearbox and wheels, avr micro and light sensors with discrete H bridges. Timothy has plans to get his robot maze solving, maybe it will be maze solving before mine.
Phil told us about creative/project/hacker/maker space in Christchurch where you can meet like minded folks to discuss and make things. Sessions are currently on Sunday afternoons and Wednesday evenings at the Canterbury Innovation Incubator, 200 Armagh Street, Christchurch. see: http://chchspace.nztech.org/
Charles Manning delivered a very practical introduction to making your own sensors for Lego NXT. Everything from how to cope with crimping the strange connectors, some really simple switch, and opto interfaces through to active blocks to more than double the NXT sensor capability. You find Charles slideshow here: http://embeddedjanitor.blogspot.com/ Charles recommended a book that parallels much of his work: http://www.extremenxt.com/books.htm
After the meeting Timothy asked me how my micromouse maze solving simulation colour character display is implimented. The complete code can be found here:
http://homepages.ihug.co.nz/~rjtp/Micromouse/Simulations/LinuxMouseSim.tar.gz
the display function is in file navigator.c Navigator_ShowMaze( ). Documentation on escape sequences can be found here: http://en.wikipedia.org/wiki/ANSI_escape_code |
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Last Updated ( Friday, 24 April 2009 )
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Meeting Report Wed 18 Feb 2009 |
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Written by RichardJones
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Sunday, 22 February 2009 |
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For those of you who were unable to make it here is a report of what we got up to last Wednesday. Those who were there feel free to email me with any corrections or missing details. The SumoBot session attracted a turn out of about 40 people and six robots. The collection raised $47.40 for Science Alive that was much appreciated. Next meeting will be Tuesday 14th April at 6.30pm in the Science Alive Seminar Room. We hope to have demonstrations of the Robocup Junior challenges (Dance, Rescue and Football) at 6.30pm and a talk from Charles Manning about DIY design and construction of Sensors for the Lego NXT at 8pm. Three Lego NXT robots came along brought by Yuito recently arrived from Japan, my battle hardened robot Gnasher and Alexs robot that I don’t have a name for yet. Yuito had a very neat reciprocating pusher and Alex has a neat set of gears that pull any loose parts off unsuspecting robots and try to haul them up off their wheels. Yuito’s dad Hiroto pointed out that my robot was too large for the rules (I should check this out). Each of the robots did a fine job of searching the ring for opponents and pushing them out of the ring. However Alex’s robot won through with an uncanny knack for remaining firmly on the board while pushing opponents out. With a bit of luck I’ll post the video soon. Peter brought along three robots from the inex collection. See: http://robokits.co.nz/Robo-STAMP-YouTube Buggy Bonzai and Sumo Tank took part in the Sumo against the NXT bots. This was an interesting match with no clear winners as the NXT’s could not move the inex bots once they had stalled. The third robot showed off the tabletop challenge wondering randomly around the table and not falling off. Andrew gave us further details about how the folks in Japan make robot wheels by machining hubs and casting rubber tyres onto them. I’m sure this technique has potential for the home workshop. There appears to be plenty more to be discovered about Sumo technology and challenge organization. If we run this event again we need more robots, scales, measuring devices and a no go zone around the ring to prevent spectators appearing to the robots as opponents! |
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Last Updated ( Tuesday, 07 April 2009 )
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Lego Sumo Practice Session. 21 Jan 2009 |
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Written by RichardJones
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Sunday, 25 January 2009 |
Nine people attended. We started a little late as the Seminar Room door was locked and although I had access to the corridor we could not get into the main room. The nice security guy turned up at about 6.35 and we went in.
Stuart, William, Scot and Tiffany brought along their NXT creation subsequently named Topple. Topple is a first generation Lego Sumo bot that had not seen active service or even a Sumo ring until the evening. Of course thats what the practice session was all about. Topple had a tendency to advance to the edge of the ring and fall off as it tried to reverse to the centre. Its a nice little twist raising the ring a few cm off the floor! When spinning on the spot looking for prey Topple had a tendency to scratch circles in the black paint of the sumo ring. Some quick rebuilding to add a caster, modify the centre of gravity and new software reduced the wear on the once new sumo ring and battle commenced. To be fair Topple was up against Gnasher, a second generation bot with many incremental improvements along the way, so Topple retired having fought bravely but not very successfully.
Vilna had some interesting observations. We started the bots back to back as shown in the lego video, and our New Year video here: http://homepages.ihug.co.nz/~rjtp/LegoSumo/RobotSumo.mov At Burnside High they built sumo bots a year or two back and the bots had difficulty finding each other when the target bot was at an angle providing little reflected ultrasound signal back to the sensor. So we set Gnasher off at an angle to the opposing bot. Gnasher immediately fell off the ring, and subsequently did not find Topple at a 45 degree angle. So there might be some improvement opportunities here. Improved search algorithms for finding bots a awkward angles, stealth bots that are hard to find, and more sensors to reduce incidence of topple.
Sue Linscot from http://www.robokits.co.nz/ brought along a tracked robot kit and which she assembled during the evening with a lot of 'help' from William and Scot. Sue decided not to enter the Sumo as the tracked bot did look small and sophisticated next to the brutish Lego bots. Maybe we should have a lightweight class just to keep things fair.
By 8pm battle was all done and it was bedtime for some of us. Sorry to those who could not make it earlier and found us gone.
Our next session is on Wed 18th Feb 2009 at 6.30pm in the Science Alive Seminar Room. Topics will be the Robo Sumo Challenge, anything else that people choose to bring along and hopefully plenty of interesting items for the free stuff table. See http://kiwibots.org for directions.
Richard Jones |
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Last Updated ( Sunday, 25 January 2009 )
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