Robot Electronics and Power - Answer Thread

[Wil Wheaton]

Is servo reverser legal? Here is the link:
http://www.servocity.com/html/sr10_servo_reverser.html

A: No. Servos may only be connected to and controlled by the HiTechnic Servo Controller or the Matrix Controller.

[Wil Wheaton]

Per post #30 HS-755MG servos were ruled as illegal because they are described as giant scale servos.

Per HitechRCD manufacturer's of the allowed HS-755HB they are described as Karbonite Giant Servo Part No: 33755S (see http://hitecrcd.com/products/servos/...-servo/product).

In looking at the specifications between the two servos the seem to be identical in all respects with the major difference being metal gears in HS-755MG vs HS-755HB.

In sites like ServoCity they are described as 1/4 scale servos (see http://www.servocity.com/html/hitec_servos.html)

In light of this would HS-755MG's be considered legal?

A: Thank you for the additional information. Yes, the HS-755MG servo is legal. The original question/answer have been updated to reflect the additional information.

[Wil Wheaton]

We are a Rookie team using Matrix. Can we use any servo with the Matrix controller or are we limited to the Matrix Servos only?

A: Only Matrix servos are to be used with the Matrix controller (according the Matrix manufacturer)

UPDATE: After additional consideration HiTechnic & Matrix have determined that the Matrix servo control circuitry is capable of handling the same limits as the TETRIX Servo Controller. The limits for servo use as listed in <R08>.h apply to both TETRIX and Matrix controllers.

[Wil Wheaton]

We are using a HiTechnic SuperPro prototype board on our robot, and were wondering if an MPU-6050 count as a legal sensor under <R08>n.iv.:

The gyro in question would only be connected to named connections on the prototype board, and would only draw power from the named power sources on the prototype board. It would also only communicate with the NXT through the prototype board.

The breakout board we are using is the GY-521 breakout:
http://dx.com/p/gy-521-6dof-mpu6050-...FRSVfgodCHQA-A

A schematic of the breakout board can be found here:
http://playground.arduino.cc/uploads...050-V1-SCH.jpg

A: Yes, the listed sensor, used in conjunction with a sensor prototyping board is legal, as long as no other rules are violated.

[Wil Wheaton]

Clarification of <R08.q>: "Power distribution splitters may also be used (and are strongly recommended) to make wiring easier."

Can we use a Anderson Powerpole RIGrunner 4000 series power distribution part for that purpose? For example:
http://www.powerwerx.com/powerpole-p...orizontal.html

I think the answer is yes but I'm a rookie coach so I'm double checking.

A: Yes, the distribution panel would be legal. The fuses all should be 20A or smaller (the size of the fuse in the battery pack)

[Wil Wheaton]

Because of a change that a TETRIX supplier made to the DC Motor, TETRIX is asking teams to replace the gearboxes on DC motors that were shipped this season. Will replacing the gearbox on these motors violate any rules?

A: Modification of TETRIX Motors shipped in the 2013 Kit of Parts (part #739083) will be allowed, only using the replacement gearbox provided by TETRIX and following the instructions from TETRIX. No other modifications are allowed. Be prepared to explain the modification to the inspectors at your event.

Much thanks to Pitcso/TETRIX for developing a quick solution to the gearbox failures that are plaguing some of the motors.

[Wil Wheaton]

hello,
can we control cube picking mechanism and flag raising mechanism into one dc motor? while we are sweeping the cube, flag raiser also will turn, however we are not going to locate our robot to flag raising zone until the end game. and this mechanism is not going to damage any other robot.

A: There is nothing in the rules that prohibits a motor being used to drive more than 1 function in a robot, as long as no other rules are violated.

[Wil Wheaton]

Can we use a servo reverser such as this one

http://www.hobbytown.com/Shop/Futaba...ervo-Reverser/

Thanks.

A: No. This has been previously answered (11/19/13). Make sure to completely read the FTC Forum before posting new questions.

[Wil Wheaton]

Hi

We had issues with all the matrix servos supplied with our competition kit stripping gears and becoming unusable, so we ordered replacements from Matrix Australia over three weeks ago and we still haven't had a response from them or had them supply our parts. In order to compete in the Australian Nationals we used replacement servos Hitec 311 180 degree rotation but I just discovered
Servos for Matrix Controllers
in your forum saying these would be illegal as the Matrix manufacturers don't allow non Matrix servos to be connected to their controller.

We also had plans to use:
Turnigy XGD 10HM
or
Turnigy 1440A

for the reduction in weight they give to our game block pickup.

Can we please have some clarification?.

A: After additional consideration, Hitechnic & Matrix have indicated that the servo controller circuitry in the Matrix Controller will handle the same limits as the TETRIX Servo Controller. The limits listed in <R08>.h apply equally to both TETRIX and Matrix systems.

[Wil Wheaton]

Are electrical terminal strips allowed under <R08>, possibly paragraphs q and/or r? The type we are considering are the type with screw terminals that are part of a plastic block. One similar to the ones found at Home Depot are the Gino-Position-Screw-Terminal-Strip found on Amazon at the address below:

http://www.amazon.com/Gino-Position-...terminal+strip

A: Yes, the indicated terminal strip is an example of the types of strips allowed with the robot construction rules. Make sure to safely insulate all connections.