2011 Minibot electronics

[Nishant]

Can you make your own logic circuitry to control the minibot instead of using the controllers?
Thanks,
Nishant

[Tom Line]

Let's expand on that. What are the wiring requirements for the minibot? Do we have to use a motor controller? What type fusing?

So many questions about the minibot, and no answers that I've been able to find in the documentation.

[ratdude747]

I think you have to use the NXT brick or hardwired switches. see 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,
F. Polycarbonate,
G. Polycarbonate glue,
If an observation is made that aQRWKHUWHDP¶V52%27PD\EHLQYLRODWLRQRIWKHUR ERW
rules, please approach FIRST officials to review the matter in question. This is an
area where Gracious Professionalism is very important© FIRST 2011 FRC Game Manual, Section 3 ± The Robot, Rev- Page 31 of 32
H. Aluminum sheet, 90° angle, uchannel, tube, bar,
I. rivets,
J. non-metallic rope or cord,
K. wire nuts,
L. cable ties,
M. limit switches,
N. no more than two common
household light switches,
O. wire of appropriate gauge (see
Rule <R40>),
P. non-slip pad,
Q. PVC or CPVC pipe,
R. PVC cement or cleaner,
S. Mechanical hardware (i.e.
screws, bolts, etc) ,
T. Loctite or similar thread-locking
product,
U. Rubber bands,
V. Surgical tubing,
W. Electrical tape and shrink tubing,
X. PWM extension cables,
Y. Universal security clips to hold
the PWM connectors together,
Z. Hook and loop fastener (may not
be used as tape), and
AA.Magnets.

my vote would be for the nxt brick...

[Duncan Macdonald]

If I am understanding the manual correctly, I thought I could hook up a circuit consisting of a battery, light switch, and motor? Legal by R92 because there is no more than one controller.

[Al Skierkiewicz]

Please check sections
4.3.14 MINIBOT
4.3.15 MINIBOT Inspection
If you use a controller it must be an NXT controller.
<R92> The following items are the only permitted materials for use on the MINIBOTS:
A. TETRIX components,
E. No more than one NXT controller with the Bluetooth functionality disabled,

[JohnHorton]

It seems like one could build it without any "brains" at all. In fact, I think a KISS design with, say, a light switch turned on by the hostbot and turned off when impacting the target, rigged to a motor directly might be the best idea. They were very specific about having " exactly one 12V rechargeable NiMH battery pack...", so it would seem they want this to be electrically driven as opposed to something mechanically launched from the hostbot.
Unless you just stick a battery on your projectile minibot. That'd be legal.

[Bruceb]

I think the battery statement is vague. Do you read it as the mini bot MUST have a battery?
It seems we could build a recoil motor with the surgical tubing??
Hmm

[Jester]

where might I find these ftc parts?

[JoesephWhite]

Originally Posted by Jester

where might I find these ftc parts?

http://shop.pitsco.com/store/default...=1&page=1&s=32

[peter1626]

I am a little confused by R92 it says that you are allowed 1 12v battery pack and 1 NXT controller, but the NXT requires 6 AA batteries thats 9 volts, so does this mean we are allowed to use both the NXT WITH its standard battery in addition to a 12V FTC Battery pack or do we have to somehow modify the NXT?

[JohnHorton]

Originally Posted by peter1626

I am a little confused by R92 it says that you are allowed 1 12v battery pack and 1 NXT controller, but the NXT requires 6 AA batteries thats 9 volts, so does this mean we are allowed to use both the NXT WITH its standard battery in addition to a 12V FTC Battery pack or do we have to somehow modify the NXT?

Well, a 9v regulator would work, but that isn't listed on the components allowed.I find it kind of odd they don't allow basic electronics (resistors, caps, etc.) for the minibot. Correct me if I'm wrong.

I think a simple DC loop of Battery - Lightswitch - motor(s) - back again might be the best, as far as electronics go.

[Al Skierkiewicz]

Since R92 is a list of the permitted parts and the NXT requires the AA battery pack, I would expect that those batteries would be legal. Since the only motors allowed are Tetrix motors that cannot be driven directly by the NXT, the NXT battery will not provide power to drive motors. (See above post of R92)

[Jon236]

Maybe it's time to teach the students how to make a speed controller (1/2 H-bridge....since all we want is a one-way trip (powered, at least!))

[ATannahill]

Originally Posted by Jon236

Maybe it's time to teach the students how to make a speed controller (1/2 H-bridge....since all we want is a one-way trip (powered, at least!))

You can have your one way trip, I don't want the field reset team to pull out a shotgun to get our minibot down.

[EricVanWyk]

Is it legal to have a tether wire between the robot and the minibot? Wires are allowed in R92X, but I'm not clear whether or not the sizing box in R91 precludes them.

My apologies if this has been discussed elsewhere, it is impossible to follow all these threads!