Electrical

[Professor Proton]

Use of Snap Plug Connectors: I see above you've said no to power distribution blocks. But are snap plug connectors allowed? (see McMaster-Carr 71285K86). These are inline connectors that replace a splice and make it easier to swap out motors.

Our robot has some complicate wiring and it would be much easier to swap out motors using these connectors (since we want to direct solder the wires to the terminals).

Yes, insulated snap plug connectors are allowed for the described application. Teams may use the insulated connectors specified in the question or equivalent insulated connectors from other suppliers.

[Professor Proton]

We have a DC motor with an encoder that is placed too far away from the motor controller to connect the encoder cable. Two questions:

1) Is it legal to extend the encoder cable? We would have to cut the connector plug off one end.

2) If it is legal to extend the encoder cable, is it legal to put our own connector plugs on the end of the modified cable so we can connect/disconnect at the extension point or do we have to solder the extension wires together?

Thank you!

1) Yes, per rule <R11>c.
2) Yes, it is legal to put your own connector plugs on the end of the modified Shaft Encoder Cables.

[Professor Proton]

Can we splice or make our own RJ12 cables for the LEGO motors and/or sensors?

No, only LEGO approved NXT extension cables are allowed. See rule <R5>b9.

[Professor Proton]

Obscure Ruling Request from FTC 4234 and 7

We have come up with an interesting modification that allows us to keep our power blocks on the motor without resorting to zip ties, soldering, etc. We’ve drilled and tapped small setscrews into the clip posts so we can lock the block onto the motor tabs. Is this modification allowed?

No, the TETRIX Motor Power Cable is an electrical component and may NOT be modified as stated in rule <R11>b.

[Professor Proton]

May we use Mindsensor parts on our prototype board?

Yes, so long as the constraints specified in rule <R5>d are followed.

[Raj]

Can we add COTS inline fuse with the TETRIX MOTORS? eg. an automotive inline fuse holder.

A: No. That would be considered an electrical modification and not allowed. However, you may purchase the TETRIX® Fuse Protected Motor Power Cable (part #W736465 from parts.ftcrobots.com) and use that.

[Sheldon]

1. Is it legal to solder NXT cable female connectors to the protoboard (available from mindsensors) and use that to interface with standard NXT and hitechnic analog sensors through the analog ports? This would help us avoid using a SMUX and dealing with yet another battery that can go dead.

2. Closely related to the above, is it legal to cut one end off an NXT cable and solder the exposed leads directly to the proto board to interface a standard analog sensor? Or is that considered modifying an electrical part? (There is a grey area here because you do allow some cables to be cut and extended, and this is a similar concept.)

1) Yes, this is legal.
2) No, you may not modify the NXT cable.

[Professor Proton]

Can we use COTS miniature micro-switches as sensors with the NXT protoboard?.

Yes, so long as they are used in conjunction with the HiTechnic Prototype Board.

[Raj]

Our robot design is using one of the Mindstorm interactive servo motors (W979842) but the NXT connector cables that were supplied with the kit are not long enough for our design. We ordered longer cables but they haven't arrived and our first competition is 12/11/2010. Can we purchase longer communication cables from some place like Home Depot or Radio Shack?

A: No. If you look close enough at the connectors, the clip for the fitting is offset from the center of the cable (unlike an RJ11 or RJ45 cable). That's why we require official NXT cables from LEGO or from HiTechnic.

[Professor Proton]

Since we do not have time to get longer cables, can we use extension blocks from Home Depot or Radio shack to connect multiple cables together?

No, this was previously address in post #13.