Marble Miser was designed to meet the challenge of the 4th Annual Lego Robotics Competition \/ Get together at U of T in Toronto Ontario.![\"\"](\"\/image\/marblemiser\/main.gif\")
\n Many thanks to Calum and the boys for putting this together.\u00a0 It was the first event that I was able to attend, and it was a great time.\u00a0 The turnout yielded many more entrants than initially expected.
\n To find out more about the event, visit RTL Toronto Website.
\n Now to get down to details.<\/p>\n
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![\"\"](\"\/image\/marblemiser\/angle.gif\")
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\n This view shows the parts of Marble Miser that do the object avoidance tasks.\u00a0 In total, Marble Miser has 6 sensors multiplexed to the 3 sensor ports.
\n Port 1 has 2 touch and 1 light sensors.
\n Port 2 has a rotation sensor
\n Port 3 has 2 touch sensors.
\n This only required one trick in NQC.\u00a0 For Port 1, I had to be able to distinguish between when the “bumper” was hit, and what light sensor values were being returned to the RCX (white\/black marble & home bases).\u00a0 To do this I set the port to read as RAW.\u00a0 Distinguishing between the tasks of bumper detection and colour\/light reading was simple:
\n If sensor value < 70 then
\n do avoidance rountine (bumper hit)
\n end if
\n If sensor value was in the range of 650+ then read light values and do marble detection rountines.<\/p>\n
![\"\"](\"\/image\/marblemiser\/top.gif\")
\n The top view shows the front bumper system and the marble guide.\u00a0 The marble guide was driven by a micro motor that was powered seperately by a 9V battery pack.\u00a0 This power source also powered the fiber optic unit at the back (for show only).\u00a0 The power source can be seen directly below the RCX to the left of the motor.\u00a0 I was very impressed with the sensitivity of the bumpers.\u00a0 The top set were very flexible, and could absorb shock if Marble Miser was in a bind with another bot, and could not get out of it (see below).\u00a0 The bottom bumpers were initally designed to server 2 purposes.\u00a0 First, to guide the marbles into the center feed area, and second to detect hits on walls etc.. \u00a0 They too worked quite well.<\/p>\n
![\"\"](\"\/image\/marblemiser\/under2.gif\")
\n This is the marble guide system.\u00a0 Quite simple.\u00a0 Through forward motion, the marble would be guided into the detector unit (keeper\/ejector). \u00a0 There, the light sensor would read the value.\u00a0 The keeper\/ejector is the 2 blue 3x beams.\u00a0 They are attached to a micro motor, that runs through a rotation sensor.\u00a0 This unit would rotate one way to keep, and the other to eject.\u00a0 The rotation sensor is used to enable the unit to return to a zero position.<\/p>\n
![\"\"](\"\/image\/marblemiser\/rumble.gif\")
\n Here Marble Miser gets in a bind.\u00a0 Marble Miser was programed with “get out” routines, but since one drive wheel was raised off the ground, it was unable to break free.\u00a0 This competition ended up in a tie.\u00a0 Notice the tubing at the rear taking a beating.\u00a0 For the most part, this helped when Marble Miser was in tight corners, as it guided it around the turns while allowing flexibility.\u00a0 Looking back, I would not have built it any other way.
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![\"\"](\"\/image\/marblemiser\/comp1.gif\")
\n Two interested onlookers having fun watching the competition…<\/p>\n
![\"\"](\"\/image\/marblemiser\/comp2.gif\")
\n This was one of Marble Miser’s better performances.\u00a0 During this competition, my home base was white.\u00a0 The goal was to collect as many white marbles and get back to home base before 5 minutes was up.\u00a0 Well at the 3+ minute mark, Marble Miser had collected some 5 marbles in its holding bin and got back to home base and got stuck in the corner, so I was happy to let it keep trying to get out.\u00a0 Lucky for me it didn’t!\u00a0 I got 16 points for this round.<\/p>\n
![\"\"](\"\/image\/marblemiser\/comp3.gif\")
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Rate This Post: Marble Miser was designed to meet the challenge of the 4th Annual Lego Robotics Competition \/ Get together at U of T in Toronto Ontario. Many thanks to Calum and the boys for putting this together.\u00a0 It was the first event that I was able to attend, and it was a great time.\u00a0 The turnout yielded many more entrants than initially expected. To find out more about the event, visit RTL Toronto Website. Now to … Continue reading ![\"1](\"https:\/\/www.plastibots.com\/wordpress\/wp-content\/plugins\/wp-postratings\/images\/stars\/rating_off.gif\" "\\"1")
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