Number of Motors?

The rules say that you are allowed to have 4 motors. However, at Lego Fever I yesterday during our robot presentation, the judges told us that we were only allowed to have 3. Can someone help clarify this for me?


This year’s rules say you are allowed 4 motors. The judges are likely basing their ruling on past year’s rules, which limited you to 3 motors.

Judges shouldn’t be making that call anyway. We train our judges to not make a call on the legality of the robot. Referees are supposed to make that call. And four motors are legal this year.

Can the NXT support 4 motors?

No, but the idea (with the NXT) is to have 2 motors, each with an attachment and swap them out. This was prohibited in previous years.

(I should mention that there are third-party motor duplexers like this one that allow you to connect additional motors to your NXT, but as third-party hardware, they are prohibited hardware for FLL competition.)

The FLL Nature’s Fury Rules book states:

[quote=Rule 4 - Equipment > Motors]You are allowed a maximum of four MINDSTORMS motors in the competition area. Choose your
favorite combination from among the LEGO-manufactured types shown here. No other motors are allowed.
[Allowed LEGO motors are pictured]
Quantity limits don’t just apply to what’s on your robot “right now.” The referee (the “ref”) adds up everything
you have with you in your boxes, your hands, your trays, and on the table. All of it counts towards your total.
— Example: If you have three motors permanently built into your robot, but wish to cycle through several motorized
attachments during the match, your design needs to allow the last (4th) motor to be traded in and out from one
attachment to the next when needed.
— A fifth motor in the competition area is not allowed, no matter what.
— Even if you plan to run only four motors at a time, a fifth motor is not allowed.
— Even as a spare, a weight, or a decoration, a fifth motor is not allowed.[/quote]

The NXT only has three output (motor) ports, while the EV3 had four. Anybody, including people using NXT or RCX, are now allowed four motors. In the past it has traditionally been three motors, hence the confusion.