Sumo Bots B/C [Trial]

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Re: Sumo Bots B/C [Trial]

Postby ichaelm » July 26th, 2010, 7:27 pm

I hope that isn't a rule next year, but who knows...

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Re: Sumo Bots B/C [Trial]

Postby gh » July 27th, 2010, 6:57 pm

As for electronic braking: yes, do it. All decent commercial motor controllers can do electronic braking by "shorting the motor terminals." This forms closed loops in the motor's windings (in the rotor for an plain-jane brushed DC motor), which resists change of magnetic flux (e.g. the rotor rotating in the field[s] of the permanent magnets surrounding it) by Lenz's law.

For various reasons, this will also cause brief, but sharp, voltage spikes as back-EMF from the motor, so I'd really recommend not building the motor controller yourself. This isn't because it's dangerous, as hobby motors don't have the winding inductance to store (and thus discharge) any unsafe amount of energy, but because it's not easy to build something that won't get fried every time you brake hard.
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Re: Sumo Bots B/C [Trial]

Postby ichaelm » August 3rd, 2010, 5:58 am

Thanks gh! I just finished building the signaling circuit, so all I have left is the motor driver. I breadboarded a simple one that worked fine with the motors I have now, but since I might get some more powerful motors in the future I think it would be best to take your advice.

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Re: Sumo Bots B/C [Trial]

Postby gh » August 3rd, 2010, 7:06 pm

By all means, keep working on it; it's a very good exercise and I expect that you can get some nice results. Good luck with the project!
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Re: Sumo Bots B/C [Trial]

Postby ichaelm » August 4th, 2010, 4:23 am

Thanks!

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Re: Sumo Bots B/C [Trial]

Postby fmtiger124 » August 12th, 2010, 6:48 am

That can be true- but the cheering is very annoying. Before the bout, fine. But during it... that's a different story. I mean, at 09 states, I was very, very nervous to go up against Eagle Hill (I know you probably went there, so no offense) and I think I may have won if I hadn't been so nervous. But I was, my fingers were shaking, and I lost. I'm not bitter, but I think that quiet and keeping the crowd away from the ring (again, at 09 states they got right up against us) are good improvements.
I didn't....I went to Wellwood the one nobody's ever heard of (despite the fact that we've been relativity close to unseating eagle hill the past couple years at regionals and have been top 5 at states the past few years).
That's my primary concern- crowd control is minor compared to this, but they're pretty related. At 2009 states (I know I talk about this a lot) there were some people using cell phones to record and even talk through the bouts. It messed up my bot for a while. There will be no way for this to be controlled on the National level.
My suggestion. Set up a live feed to another area. The feed can show everyone what's happening, but there is no excessive crowd noise and no interference except for the one camera for the feed. At 2008 Nationals they had a projector screen for Robo-cross- just expand on the idea. They certainly have the resources.
The phones I understand....perhaps they could have a camera there that records the bouts and teams can buy tapes or something?
As far as a feed somewhere else.....I think that would take away from the excitement and appeal of the event. Also, I expect it would get extremely crowded and likely hard to hear anything. Not to mention I'd think there's potential that it ends up far out of the way so people can't go to it because they'd end up late for other stuff. Personally, I would set up bleachers perhaps around all 3 sides of the ring. and hey....earplugs wouldn't be such a horrible idea either.
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Re: Sumo Bots B/C [Trial]

Postby paleonaps » August 14th, 2010, 10:17 am

Thanks for understanding. I like the tape idea, but I don't think many people would buy them. The live feed doesn't need sound, and it could be in some sort of auditorium, so everyone could sit. I will also contemplate earplugs.
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