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Robot Vacume Cleaners
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dyrodium
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Joined: 24 Aug 2004
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Location: Sydney


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Yeah actualy rare earth magnets are getting quite cheap, a few above a low steel plate would work quite well i would think. Smile And usefull if you'd like to recover bolts or other things other then rummaging through the dust collector! Smile
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Post Tue Jul 26, 2005 8:42 pm 
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andrew



Joined: 16 Jun 2004
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Location: Castle Hill, Sydney. N.S.W


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hmm, thats a very good idea actually. for loose bolts and shavings etc etc.

Or anybody who has access to computers theres strong magnets in floppy drives or hard drives or something as nick has a heap of these magnets that are from hard drives or some part of a computer and they are rediculously strong. would pick up things easilybeing a good 4 cm or 7 even off ground im guessing.
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Post Tue Jul 26, 2005 9:05 pm 
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Spockie-Tech
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Problem is, electromagnetic Force varies inversely as the square of the distance.. ( I awlays wanted to say that.. Wink)

Or in plain language, if you double the distance from a magnet, the field is 4x as weak, 3 times as far, and its 9x as weak, so you need a hugely powerful magnet to operate at any appreciable distance.

Probably the best bet would be some form of ferrous metal grid that the airstream passed through with magnets attached to it at strategic places. it wouldnt grab aluminium bits, but most bolts/bearings etc have ferrous metals in them, so it should stick to most of the bits people are likely to want to recover..

At the last RoboWars, I had to go an scour the arena for a nut and bolt off I.G.'s drive adapters. The bolt was easy, the nut had hidden down in the vertical gaps at the side of the arena.. Rolling Eyes
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Post Wed Jul 27, 2005 12:23 am 
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kkeerroo
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Joined: 17 Jun 2004
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Just get the air to spiral up the vacume tube so that heavy particles travel up the wall of the tube where the magnets can be placed.
Or you could just take some spare nuts and bolts with you when you go to a comp so you don't need to look for lost ones (I remember the Aggressor was always loosing screws whenever it moved so we always had a couple of packets to replace missing ones between fights).
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Post Wed Jul 27, 2005 8:06 am 
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dyrodium
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We should just attach a magnet to a stick and scan the arena after each match, for missing bolts. Smile (only problem is that our floor is steel. Sad )
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Post Wed Jul 27, 2005 8:28 am 
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Totaly_Recycled
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The magnets in vertexs disc will pull a 12 inch shifter out of your hand at a distance of 50to 70mm but it needs 80 amps at 24 volts to do so Very Happy

Post Wed Jul 27, 2005 9:55 pm 
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DavidM



Joined: 07 Jul 2004
Posts: 41
Location: Victoria, Australia, Earth, Milky Way Galaxy


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There's a book called "Mobile Robots" by the guys at the MIT robot labs. The first robot in the book is a absolute cracker, it controls two motors and effectively does the autopilot - bounce of the wall thing - with no processors and only a handful of parts (4 resistors, 2 capacitors, 2 transistors, 4 diodes and two relays). The construction is done on one of those white plug in experimenter boards - ok for vacuums probably not combat!

Provided the robot moves slow the simple controller would work fine, if its fast the relays and motors will take a hammering and the change in acceleration would take its toll on the chassis.

Another book "Vehicles" by Braitenberg, although not nuts and bolts one like "Mobile Robots" does illustrate the kind of behaviours that can be created from simple robots using analog circuits as very very simple neurons.

Off course the big advantages are its simple to build, cheap, not voltage sensitive, and more immune to EMI than Mr Pic or Atmel.
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Post Thu Jul 28, 2005 10:01 pm 
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Rotwang
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Joined: 15 Jun 2004
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Cool, so it might not be too hard to do the electronics then. Smile

I was intending on having horizontally spring mounted wheels on the front and corners with micro switches to detect impacts and relatively low speed.
A direct impact into a corner concerns me a bit as it would be necessary to reverse out. Not a problem for the bot, although it only sweeps when going forward.
The thought of it going too fast and hitting the wall head on conjures visions of all the dust and debris g forcing itself back out the intake and leaving a pile of rubbish where it hit, not a good look.
Do you think ultrasonics or similar could be used to detect arenas wall to allow higher speed?

The other thought I had, would it be difficult to have it running on auto then switch it to manual with the TX.

I could easily use servo switches and one channel to change over but the Idea of the ibc connecting to the auto pilot controller and the rx at the same time worries me, once again as an electromechanical person I would probably just put a multy pole relay to swap them over.
It’s just if the next fight is getting close and the Arena Sweeper keeps missing a spot someone can switch over to manual and clean up the spot and drive it out.
It will be a little on the heavy side for easy lifting by one person.

Post Sat Jul 30, 2005 4:19 am 
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Valen
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i always thaught magnetic field was a cube law (n^3) ?
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Post Tue Aug 02, 2005 10:00 am 
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Glen
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inverse square law i was pretty sure. wait till i study for physics then ill tell yeh Razz
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Post Tue Aug 02, 2005 5:49 pm 
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Rotwang
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Joined: 15 Jun 2004
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Location: Vic


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Making a little progress on Arenasweeper as I call it nowadays.
Its motors and batteries are wired to the IBC.
Its frame is only tacked together but good enough for a test, just have to find a few more parts that have somehow gone missing over the last few months and I can give it a test. Very Happy

Post Sat Nov 19, 2005 10:28 am 
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Big AL
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Joined: 16 Oct 2004
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use the cleaner to find em Very Happy
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Post Sun Nov 20, 2005 10:59 pm 
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Rotwang
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Joined: 15 Jun 2004
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Location: Vic


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Got it going all right and we had fun driving it in the house as I mentioned in one of the other threads.Smile

Later that day I popped into Robs room to check on his new Kittens [anyone wont a new cat] and got caught watching something on his TV.

It got dark, sun went down, and I walk out into passage and fall over Arena-sweeper where I had left it sticking my hand out to save myself from falling only to stick it through the glass front of the grandfather clock cutting myself in the process. Sad

There is probably a moral there someplace; maybe big heavy bots need led’s on all the time so you can see them in the dark. Confused

Post Mon Nov 21, 2005 3:03 am 
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Rotwang
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Joined: 15 Jun 2004
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Location: Vic


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Ok Arena Sweeper has been to two events now; Robowars at sidetracked where the crummy radio I had hooked up was so bad that the TX had to be within 3 metres of it to work. Sad

With Vincent doing a good job keeping the crowd entertained and plenty of other fillers he didn’t do a lot.

Brisbane gave him a real work out; what with all the demo sessions smashing old laptops play stations, DVD players etc. I was very pleased with his performance. Very Happy

One feature that I had in mind was a fan to just assist the brushes to draw the dust in. I will try to find the time to do this before his next outing.
Only damage suffered was a chunk out of one of his brushes curtesy of Bender.

Post Mon Apr 10, 2006 10:23 am 
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