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Originally posted by assassin:
rjw thats a bitchin little bot you have there. What are the problems/issues with it, what do you NEED to improve?

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Link to possible beatle brushless motors


http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8144&Product_Name=Turnigy_2627_Brushless_300-Size_Heli_Motor_4200kv

Can't say that I've tried or even seen these, but the price and specs seem reasonable.

What are your thoughts on a single larger motor driving 1 wheel like spambutchers designs? Think it'd go ok with the brushless alternative?
Cheers !
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What do you think of something like an IR beacon rather than using the accelerometers?

or perhaps use a wheel rotation sensor?
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Mechanical engineers build weapons, civil engineers build targets

quote:

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Originally posted by dyrodium:
What are your thoughts on a single larger motor driving 1 wheel like spambutchers designs? Think it'd go ok with the brushless alternative?
Cheers !

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quote:

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Originally posted by Valen:
What do you think of something like an IR beacon rather than using the accelerometers?

or perhaps use a wheel rotation sensor?

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My understanding is you use the accelerometer to infer your rotation rate, then use that as a time base for your motor speed up/down commands and "direction" output LED.

Watching the videos the direction output LED seems to indicate the melty system is very prone to drift in the short term (which using a 2nd or 3rd integration for position with a noisy input is going to happen)

Putting an IR beacon in the arena, as the melty spins look at the beacon for positioning information. Use that as the basis for the speed up/down, and you should see no drift in the long term (seconds).

Adding a rate gyro to the mix will let you infer position throughout the rotation to take out any bumps or the like (which seem to be the main cause of drift) and would help with drift even if you don't go with the beacon.

the wheel speed sensor is just another way of getting the rotation speed, you only need one integration to get the rotational velocity then rather than two, so you could wind up somewhat in front.
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Mechanical engineers build weapons, civil engineers build targets

In my case, I would not add anything, in that the robots seems to work pretty well. I'm spinning them a lot faster than most and imo floor conditions and my bad driving skills are the 2 biggest problems.

I'm sure that there is plenty of room for improvement, but at the moment I'm happy with how they perform, except in an ejection arena of course.

I'm all for R & D, but I have other related projects that are on the burner at the moment. You should build a melty and test your ideas out....we need a lot more people doing this , to move it forward.

Herr gepounden uses an IR beacon to do its translation, the guys have a demo of it working here http://www.youtube.com/watch?v=Pjrrbg78YZ4
Much lower speed though... Can however drive normaly which other meltys can't!
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I've seen that video before, but at the moment youtube will only play a small portion of it???

Not to take anything away from their efforts, but I'm not sure of the need for all sorts of electronics, especially in a robot that might pingpong off of everything aroond it....I'v had caps come unsoldered on a br6000 receiver even though it was very well padded....kiss might be the word, unless the electronics does something totally needed and beyond what Rich's setup does.

Looks like MLEC (our educational team) has been approved by battlebots, so a 120 melty is in the near future....

We have an event at the Franklin Institute in Philadelphia in 10 days

Here is my NEW 3 pound melty sitting on top of the material for the NEW 12

the new 3 spins to around 4500 rpm








Ti armor and S7 knocker...on Colsons of course

Hope I get the 12 done in time....



Thankfully, the alu block is sponsored

Vids?
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Steven Martin
Twisted Constructions
http://www.botbitz.com

just for you...

http://www.youtube.com/user/ReadytoRumbleCombat?feature=mhum#p/u/6/ZpoOhHG6uIw

Epic! Get some driving practice in.
Curious who sponsored you with that huge chunk of ali?
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