How to control the minibot?

Hi,
We finished designing our mini bot but I thought on a problem.
How to get the motors work when we need(when it is on the tower)?
I thought of a touch sensor and NXT block to activate the motor but because we don’t have FTC we don’t have the motors controller(to get the minibot being controlled we need NXT block, touch sensor, motors, battery and the motors controller). So how can we solve this without this part?

You can use a light switch to control the bot without the need for the Controller. Design a mechanism to turn on the light switch when the minibot is in position to climb.

Limit switches and common household light switches are legal items to control the motor if you dont want to use the NXT and motor controller.

Is there a rule saying that the mini bot motors cannot be running at the start of the match?

I haven’t seen it if there is… but then again, I haven’t been keeping up with Q&A as closely as I sometimes do.

Now that I think about it, I’m not even sure where it says they have to stop at the end of the match, so long as you have a way of quickly getting the mini bot back down the pole.

Jason

I’m not completely positive, but I don’t believe there’s a rule against that. However, doing so will most likely drain the minibot battery fairly quickly.

Hi, I don’t know if this would help, but you could probably use a deploy system, and then use a switch that would trigger once it touches the pole, causing the motors to activate and drive the minibot up the pole.

Jason,
I think this is the defining rule…
<G19> MINIBOTS must remain completely autonomous and move up the POST solely through electric energy provided after the start of DEPLOYMENT by the permitted, unaltered battery and converted to mechanical energy by the permitted unaltered motors (and associated, appropriate circuitry).
I think that implies that the motors may be running but the minibot may not move vertically until after the start of deployment. Q&A is the place to ask.
However, simple switches can be employed to start, reverse and stop the minibot if one thinks about it.

Hey, Dose anyone know if we will be able to use a ladder to get the mini-bot down from the pole

I saw this on another thread. That you can not use a ladder, pole, or another type of tools to get the mini-bot down. And you must get it in a safe manner.

GDC says no ladders: http://forums.usfirst.org/showthread.php?t=16331&highlight=ladder

But they haven’t said if any other devices are allowed.

EDIT: And now they have said - see Team Update 6.

Are basic electrical components allowed for use on the minibot, like capacitors and photoresistors, to trigger and disable the robot?

I don’t see them on the list of allowable parts… (Indeed, I’d love it if we could use regular resistors…)

Since a relay is like a switch are we allowed to use one in a custom circuit?
Not talking about a Spike relay, but a normal one.

The student that is in charge of the FIRST Q&A didn’t show up tonight.

Guys the list of allowables on the minibot is very specific. Relays are not on the list, components like resistors and photoe sensors are not on the list, except those that are Tetrix parts when used with the NXT that are on the list here…http://www.usfirst.org/uploadedFiles/Robotics_Programs/FRC/Game_and_Season__Info/2011_Assets/Approved%20Tetrix%20Parts.pdf

I have to ask, what would you use the resistor for?

…to make it come back down nice and slowly under drive without a controller.

Patrick, It will do that if you remove power from the motor and short the leads of the motor. This is the technique that is in use when you select “brake” mode on a speed controller.

This is what our team is doing. all it is, is a limit switch from the kit last year, wired so that when we hit the pole, it sends a signal to the motor telling it to start.

I don’t think minibots are going to come down nice and easy. i would build one to with stand a fall from 122 inches. take a pole vaulters advice, hitting the ground will not be fun. ten-and-a-half feet, you would want a nice thick pad to fall on. build it so it can take the fall, and be ready to rewire if need be.

Of course, of course, and as a physics teacher I already know that… :wink: But it’s only true if your MINIBOT back-drives down the pole in the first place – which ours currently does not. Thus, shorting the motor leads will result in it continuing to not come down at all, instead of coming down slowly.

It’s all good. Just more stuff for the kids to figure out!