Electrical

[Administrator]

Reply to this post to ask a question about Electrical components in your Robot.

[Raj]

4.1 <R5> b 2 refers to the power source for the NXT controller. This seems to preclude the use of the new Lithium Ion battery available for the NXT. Is that intended?

This is not true. There is a typo in Rev. 1 of the Game Manual. The two allowable batteries for the NXT controller are the AC and DC batteries (part # W979798 and W979693). The 93 was inverted to 39. This will be corrected in the next release.

[Sheldon]

Are we allowed to use infrared distance sensors with HiTechnic Prototyping board? Infrared distance sensors will emit infrared beam. Will they be considered as disturbances to IR beacons and IR sensors?

No, per Rule R5 d8 only visible light LEDs may be used. These LEDs can only be used for decoration or signaling.

[Wil Wheaton]

Rule <R5 d8> would seem to preclude the use of visible-light LED's as part of an active sensor. Is it allowable to use visible-light LED's to supply light for sensing purposes (E.g.: visible-light proximity sensors, reflectivity sensors, active color sensors.), so long as they do not interfere with other robots or the Field Control System?

The current robot construction rules do not allow the use of visible light LED's to create sensors. The rules only allow them to be used for signaling and/or decoration

[Wil Wheaton]

The game manual appears to rule out the use of external power sources for decorations (<R5>f). However, at last season's World Championship there were several robots with large numbers of LEDs that could not have drawn enough power from the protoboard which can only service a few standard LEDs on it's 20ma limit. Is it permissible to hook a string of LEDs with suitable resistor into a motor controller output and use motor control programming to turn them on and off for either signaling or decorations? If not, then wouldn't that make it impossible given the restriction against external decoration power sources and the limits of the protoboard's power output to have dozens of LEDs decorating the robot? (I ask this not to cast any aspersions on last year's teams who did this, but because our team thinks it looks really awesome to have tons of LEDs decorating the robot and we want to make sure we can do it legally!)

We cannot comment on what was/wasn't allowed at past events.

Current robot construction rules do not allow for external power for any use, including decorations.

[Barry]

We'd like to purchase another Samantha module (including mounting bracket and power connection) for a previous year robot. I can't find where to buy one. Can you point me in the right direction?

For the 2010-2011 FTC Season, each registered FTC team will receive 1 Samantha module in either their competition kit or their software upgrade kit. We are unable to make additional modules available for purchase at this time.

[Raj]

the rules state that motors and other electrical devices cannot be modified in any way. Does this include the final output of the NXT motors? One of the teams from last year's final had drilled out the output to use a steel shaft. Is this a legal use? It does not change the electrical properties of the motor or the gearing, it simply allows the use of a more robust axle.

We cannot rule on the legality of last year's play. As per <R11>b, "Motors, sensors, controllers, battery packs, and any other electrical components may NOT be altered from their original state in ANY way."

[Wil Wheaton]

I would like to respectfully request that the ruling on use of IR and Visible Light in custom sensors be re-evaluated. Specifically, can we be allowed to use IR and/or visible light sensors for ground line detection similar to the (presumably) legal IR and Visible Light active sensors:
NXT EOPD (NEO1048), NXT Color Sensor V2 (NCO1038), and LEGO Mindstorms Light Sensor(9844)

Personally, I don't follow the rationale behind restricting using visible light as part of any kind of custom sensor (insight into the thinking behind this ruling would be greatly appreciated).
For IR LEDs I do understand the concern about interfering with the IR beacons, however I think allowing custom ground line detectors to use LEDs is a safe exception because the ground facing orientation will naturally make them non-interfering.

Arbitrary light sources in sensors would create a high burden on the robot inspection process.

Each would need to be tested to ensure that there is no unintended interference.

The existing sensor set provides much, if not all, of the same types of capabilities (aside from form factor) as the ones you appear to be advocating for.

[Wil Wheaton]

There is no definition of "Sensors" (R5d4). Are standard potentiometers allowed? And, assuming they are, are the mounting parts for the shaft legal for mounting that unit? (e.g. nuts and washers)

(Note: Physical dimensions similar to http://www.radioshack.com/product/in...LAID=107590082)

Hardware that comes with and is used solely to mount potentiometers would be allowed. The same is true for mounting hardware that comes with other types of electronics that are being connected via the prototype sensor board.

[Professor Proton]

Is the final output mechanism on the NXT motor assembly considereed to be part of the motor, or part of the gear train?

Quoting <R11>b: Motors, sensors, controllers, battery packs, and any other electrical components may NOT be altered from their original state in ANY way.

Therefore, all components, parts, elements, etc. contained in the NXT motor in its original state as sold by the LEGO corporation shall NOT be altered in any way.

The final output mechanism (orange disk) of the NXT motor may not be modified.