Re: 2011 Minibot electronics
 

I meant one-way powered......after contact with the sensor, the 1/2 bridge is turned 'off' and the mini coasts downward.

Re: 2011 Minibot electronics
 

While only the GDC can say for sure, I am assuming that tethers would be illegal because of the 12x12x12 sizing box requirement and by the usual no-entanglement rules.

Re: 2011 Minibot electronics
 

Erik,
From Section 1
MINIBOT – an autonomous vehicle designed and built to perform specific tasks when competing in the 2011 competition LogoMotion. The MINIBOT must obviously follow a design approach intended to play the 2011 FRC END GAME and must be compliant with all MINIBOT rules defined in Section 3.4.14.

And from Section 1.5
The match ends with robots deploying minibots, small electro-mechanical assemblies that are independent of the host robot, onto vertical poles.

I read those two references as not tethered. The Q&A will be the only place to get an official answer on this question.

Re: 2011 Minibot electronics
 

Thanks Al

After reading those sections, I agree with your interpretation.

Re: 2011 Minibot electronics
 

I believe their assumption was that if you are using the NXT, it drives a PWM signal out (at least, I believe that's how it drives the servo motors used in FLL). You would use that to send the duty cycle to a motor controller which in turn would actually use the 12V battery to power the motors.

Re: 2011 Minibot electronics
 

The allowed Tetrix motors are ordinary DC motors. You can power them directly from the 12V battery through a light switch if you wanted.

In FTC, the NXT connects to the HiTechnic motor controller which converts the I2C from the NXT brick to control an HBridge powering the DC Tetrix motors.

Re: 2011 Minibot electronics
 

That begs the question, can we fab our own parts? I'd love to skip the NXT controller and just build an H bridge run by a flip-flop. State 0 on it would be triggered by the "launch" command from the hostbot, sending the motor forward and State 1 would be triggered by a switch on top, when the minibot hits the target, reversing the motor so that Dean Kamen won't go after my bot with a pole saw.

However, they don't list discrete components on the list. I guess that's something for the Q&A.

Re: 2011 Minibot electronics
 

My interpretation is, if it is not on the list, it is not allowed.
Well, since you can bring any number of minibots to competition, just bring one per match and let THEM figure out where to apply the pole saw! :eek: (Just kidding, of course. <G59> covers it).
I read <G22> as not tethered as well.

Re: 2011 Minibot electronics
 

Oh dear, tape measures:eek:

Re: 2011 Minibot electronics
 

<R92> The following items are the only permitted materials for use on the MINIBOTS:
A. TETRIX components,
B. no more than two motors (PN W739083),
C. exactly one 12V rechargeable NiMH battery pack identical to those supplied in the FTC kit of parts (PN W739057)
D. No more than one HiTechnic DC motor controllers,
E. No more than one NXT controller with the Bluetooth functionality disabled,

The motor controllers are driven from the NXT outputs.

Re: 2011 Minibot electronics
 

Again what do you all think. R92 d sayes exactly 1 battery pack. Do you think that means we HAVE TO HAVE a battery??
Bruce

Re: 2011 Minibot electronics
 

Without specifying a required wiring schematic, I think that IF we want a battery, it has to be the battery they specify. But I don't read anywhere that we HAVE to have a battery.

GDC just want to make our brains hurt!

Re: 2011 Minibot electronics
 

Does anyone else find it frustrating that we must use the FTC kit to build the mini robot? There are no FTC teams near us that I know of so the only way we can do this is to buy a kit and they are already on back order.

Re: 2011 Minibot electronics
 

As per my understanding, you don't have to use the FTC kit, it just helps. Making the whole thing out of polycarb. or aluminium, using the 12v NiCd, and the lightswitches is possible, and a lot simpler than using the NXT and co.

Re: 2011 Minibot electronics
 

You can obtain a free FTC kit as part of the FIRST Choice program (ala carte kit of parts items that were not handed out to all teams) on www.andymark.com.

There are 1265 sets left as of 11:45 AM this morning, 1/10/11.

Be proactive - order now.

Please see http://www.andymark.com/SearchResults.asp?Cat=245 for instructions on how to login to FIRST Choice.