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Miscellaneous Robot Electrical Parts and Materials - Answers

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  • Miscellaneous Robot Electrical Parts and Materials - Answers

    Answers to questions about Robot Electrical Parts and Materials that do not fit into another category can be found in this section.

  • #2
    Originally posted by FTC10251

    Subject: What LEDs are legal?

    Q: RE12 says "Light Sources - Light sources (including LEDs) are allowed; these may not be focused or directed in any way". Does this just prohibit teams from adding focusing or directing elements to a light source or must the light source itself not be focused. Many LEDs have lens-like structures molded into their bodies to focus their output so that most of it falls within a specified cone. Are LEDs constructed this way illegal? Some distance sensors use infrared LEDs with lens structures over the LED. Are sensor that do this also illegal?

    A: It is not possible for us the create a list of all legal LEDs nor is it possible to rule on the legality of every single device. In general, if the LED is producing what appears to be a focused beam it is possible/likely that the inspectors and/or referees will question their legality. Any light source that runs a risk of interfering with the functioning of another robot is also likely to be deemed to be in violation of the basic fairness questions at the beginning of Section 8.3.1 of Game Manual Part 1


    • #3
      Originally posted by FTC9881

      Subject: Slip Ring

      Q: We would like to use a slip ring like this: in the wiring that connects a servo to the REV Expansion Hub. Is this permitted?

      A: No. In general, there is no rule that would prohibit the use of an appropriately sized and insulated slip ring connector. The particular Slip Ring connector that you reference uses 28AWG wiring and would violate <RE14>.j.ii wire gauge limits for PWM wiring (must be 22AWG or larger wire)


      • #4
        Originally posted by FTC5110

        Subjerct: Electrical wire gauge / total cross sectional area

        <RE14> j. specifies AWG gauge requirements for power, motor and servo wiring.

        Q: Is it permissible to use multiple parallel wires of a smaller gauge that when combined equal or exceed the same cross sectional area as required by <RE14> j. since electrically this would achieve the same outcome.

        A: No. All wires used in an electrical connection must meet the minimum specification for the type of usage based on <RE14>.j


        • #5
          Originally posted by FTC7244

          Subject: Power Rails

          Q: Would a terminal block and jumper rails like the ones listed below be legal to distribute the power to the Rev Expansion Hub / 12v sensors?

          A: Yes. The referenced terminal blocks are an example of a power distribution splitter as referenced in <RE14>.e. Care should be taken to ensure appropriate insulation of all connections


          • #6
            Originally posted by FTC8778

            Subject: Alternative Batteries

            Q: Our team believes that we have a found a suitable alternative to Tetrix and Rev Robotics 12 volt battery packs. In searching for an alternative battery over the summer, our team found a supplier which sells 12 volt battery packs identical to the Tetrix battery pack. It is a Ni-MH, sub-c cell, 3000 milliamps battery just like the Tetrix and Rev Robotics batteries. Can we use these battery packs?

            A: No. The only allowed battery packs are those explicitly listed in <RE03>. No other battery packs are allowed.


            • #7
              Originally posted by FTC12611

              Subject: Control LEDs via Digital I/O Ports

              These Adafruit LED Sequins can be powered thru digital I/O pin. Is this legal for FTC.


              A: No. <RE12> lists the approved power/control for all light sources. The digital i/o pins are not a part of the allowed connection points.


              • #8
                Originally posted by FTC12831

                Subject: Modifying Connectors for Power Switch

                Q Our team bought a Matrix power switch last year and would like to use it with the Rev Robotics Controller this year. Is it allowed to modify the wiring to use different connectors than the Tamaya connectors? We would like to modify it to use similar connectors to the Rev power switch one one side and Anderson Power poles on the other. Also the length of the wires need to be modified as well. We plan on using the same gauge and color of wires.

                A: Yes. <RE15> explicitly allows replacing connectors on wires. Care should be taken to make sure that all modifications are appropriately insulated.


                • #9
                  Originally posted by FTC1000

                  Subject: Battery for Powering LEDs

                  Q: Hi! So, can we use a battery for powering a LED Strip Light on robot?

                  A: Rule <RE12> lists the allowable methods for powering and/or controlling light sources on the robot.

                  The allowed power sources are:
                  • Battery pack as provided by the light source manufacturer
                  • Power ports on a Core Power Distribution Module
                  • Motor Control ports on a Core Motor Controller Module
                  • Motor Control ports on a Legacy TETRIX DC Motor Controller
                  • REV Expansion Hub
                    • Motor Control Port
                    • Spare XT30 power port
                    • 5V Auxiliary power port


                  • #10
                    Originally posted by FTC6109

                    Subject: Main Power Switch

                    Q: RE01 includes the MATRIX power switch part #50-0030. Is this switch the same one that is on the Modern Robotics Power Distribution Module? If it is not the same, then are teams using an all Modern Robotics Module configuration and teams using a hybrid Rev Robotics-Modern Robotics configuration required to wire a separate allowed main power switch? Thanks in advance

                    A: All robots must include a separate power switch between the battery and the remainder of the robot. The switches included directly on the various control systems are NOT sufficient. Additionally, this power switch needs to be clearly labeled and readily accessible.


                    • #11
                      Originally posted by FTC12676

                      Subject: <RG01> electrically ground the Robot frame to the Playing Field

                      Q: Hi,
                      We are using metal tray to pickup glyph which means metal tray may touch floor tiles sometimes. Is this violation of <RG01> Those that are designed to electrically ground the Robot frame to the Playing Field? if yes then can we use friction tape or duct tape to over part that may touch tiles?

                      A: No. <RG01>.i specifically calls out parts or mechanisms that are designed to to electrically ground the robot frame to the playing field and should not apply to a part of a robot designed to perform game play actions (i.e. your tray). Adding electrical tape along the contact edge may still be a good idea, as it would help to reduce the probability of the tray damaging the playing field tiles.


                      • #12
                        Originally posted by FTC12914

                        Subject: Main Power Switch with Core Power Distribution Module and Rev Expansion Hub

                        Q: At our first rookie competition, an inspector said we should put a switch between the Modern Robotics Core Power Distribution Module and the REV Expansion Hub that we have connected according to RE05 a.i. Our team marked the CPDM's built-in as the main power switch.

                        Is an additional switch required, or even recommended?

                        A: <RE01> requires that the robot battery connect directly to a Main Power Switch. Power should then be routed according to <RE05>. For your described case, the power should connect from the Main Power Switch to the CPDM. The Rev Expansion Hub should be powered from one of the power ports on the CPDM.

                        The power switches that are part of the CPDM or Rev Expansion Hubs DO NOT satisfy the requirements of <RE01> and cannot be used as the Robot Main Power Switch.


                        • #13
                          Originally posted by FTC9761

                          Subject: Extending Cellphone Camera to Make it External

                          Would it be legal to extend the cable on either the front or back facing camera of the robot controller phone so that the camera could be mounted externally and facing a different direction? The abilities of the phone wouldn't be altered or increased, just the position / direction of one of its cameras.

                          A: No. <RE15> prohibits internal modifications of electronics.


                          • #14
                            Originally posted by FTC11541

                            Subject: Battery Team Orion 3000

                            Q: Several years ago Pitsco was experiencing sourcing difficulties with batteries. That season they shipped "Team Orion 3000" batteries when ordering W39057. It is a 12v NiMH 3000 mHa battery. Is it still a legal battery.

                            A: No. The only allowed batteries are those listed in <RE03>


                            • #15
                              Originally posted by FTC12971

                              Subject:Extension cables for sensors

                              We need to make sensor extension cables as the ones available from Rev Robotics are out of stock. We have chosen this ribbon cable as it would be suitable for both sensors and servos, however, the color scheme does not match the servo or sensor cables. We are assuming that <RE14>.g only applies to power and motor cables so we can use this cable for sensors and servos.

                              A: Yes, this is acceptable cable to use. You should take care to note that the cable has a different color ordering that the stock Rev cables. It might be a good idea to try to find a cable that matches the color ordering to help prevent any potential wiring mistakes.