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Robot Inspection and Build Rules - Electrical - Answer Thread

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  • #76
    12v MATRIX Motor/Servo Controller

    Originally posted by FTC10877
    We have asked Modern Robotics Inc. for more MATRIX 9.6V motors (14-001 and the like), as our robot is built on it and we have invested in the system significantly. However, MR has told us that they don't have any more of the motors, which is quite frustrating. The RES-Q game manual suggests that we are allowed to use motors like the AndyMark AM-3102, can you confirm that this is accurate? If we are unable to source compatible, permitted motors then we will not be able to compete effectively with other teams, and will have to purchase even more motor controllers, motors, and batteries. If there are any other motors that we can use with a 9.6V Legacy Module/MATRIX system, please let us know.

    Additionally, we are considering using 12V batteries and replacing our motors with 12V versions as the 9.6V can sometimes be slow. Will 12V cause damage to the MATRIX Servo Controllers, which appear to be rated at 9.7V? Thank you.

    A: Given that Modern Robotics is selling MATRIX 12v batteries and motors to use with the MATRIX system, it would be reasonable to assume that they are compatible with the MATRIX Motor/Servo Controller.


    • #77
      Voltage Regulators and Converters

      Originally posted by FTC6559
      Although rule <RE03 - h> forbids the use of voltage converters (and rules on forum questions state we shouldn't ask since it is already a rule), we would like to ask if a 12 volt voltage regulator may be used to stabilize the power output from the batteries to the PDM to a fixed 12 volts. FTC is currently aware of USB connection issues in relation to the batteries. ( ) When the batteries are low they give off ~9.5 volts rather than 12. This low voltage is then further stepped down in the PDM to power the USBs, but if the input power is too low, the USBs fail. We feel that a voltage regulator between the battery and the PDM would alleviate the issue, allow teams to fully utilize their battery power, and correct any other issues that may be caused by voltage. Allowed 12 volt Batteries that have full charge have a voltage of ~14 volts, which widens the range of voltage, and could also potentially lead to issues, though it is unlikely. A fixed 12 volt regulator can be bought for as cheap as $1.50, making this easily accessible to almost all teams.

      Q: Since voltage regulators are currently disallowed, would it be okay in this instance to use one, or that one is allowed in the rules for this specific purpose, even if it is strictly outlined to one brand, one model, and one use?

      ~Thank you for your time
      Team 6559 Geared Reaction

      A: No. There are no allowed voltage regulators or converters. <RE03>.g explicitly disallowed power adapters or voltage converters. <RE06>.d disallows "Other electronics" (i.e. voltage regulators)


      • #78
        LED Powered from Core Device Interface

        Originally posted by FTC8686
        We were wondering if it is allowed to power a LED as a status indicator off of the PWM ports on the core device interface module. We have two LED's that flash alternatively and they will stop flashing if the program stops(if we disconnect, program crashes, etc). We assume that these are allowed as the interface module takes power from the core power device module, so its coming from the same source.
        Thanks! - FTC8686

        A: No. <RE03>.g specifies the allowed power sources for approved light sources. The Core Device Interface is not one of those power sources.


        • #79
          Can Teams Repair Damaged Modules

          Originally posted by FTC5414
          Modern robotics is offering a service to fix PDMs that have damaged regulators and USB ports. If a team has the ability to make the same repair for a fraction of the cost. Is this allowed?

          We are specifically interested in replacing a broken USB port on our otherwise perfect PDM. We would be replacing it with an equivalent USB port and it would be done by a professional with plenty of experience in electronics repair. We can get the part to fox this for less than $1, where it would cost $30+ to ship it to Modern Robotics to be fixed.

          Team 5414

          A: No. Modern Robotics repair service is the only allowed option for fixing damaged modules.


          • #80
            LED's &amp; Decorative Items

            Originally posted by FTC0516
            Hello, we have a few questions concerning nonfunctional decoration items.

            First, regarding LED lighting. We are interested in using some LED strips (example: however, this item lacks a manufacture created power source. Is it acceptable to create a safe power supply (within specifications for the LEDs) for the system, as none was provided?

            Our second question regards a GoPro (specifically, the mounting). When attached, is the GoPro (all WiFi capabilities disabled) required to fit within the 18" cube sizing constraint? It's sole purpose is to provide post match entertainment and mounting the camera higher would protect it from robot contact and offer a better viewing angle.

            Thank you,
            Team 516

            A1: LED's may be powered as listed in <RE03>.g only. A custom made power supply is not allowed.

            A2: Decorations are part of the robot and are subject to the sizing limits of the robot. The camera would need to fit inside the 18" cube.


            • #81
              &lt;RG02&gt; and Static Dissipation Chain?

              Originally posted by FTC6389
              Are we allowed to drag a copper chain attached to our robot chassis to the floor? We are having horrible static problems. When the robot touches another robot, or the ramp, or the field walls, our robot dies immediately. We have taken all other precautions with regard to separation of power and control wires, stain relieving the USB connectors, etc. We have proven through testing that the ESD event is in fact the problem.


              - The Lazybotts

              A: No. Rule <RG02>.i prohibits mechanisms or components that are designed to ground the Robot frame to the Playing Field.


              • #82
                Solenoid Legal?

                Originally posted by FTC9761
                Is a 12v solenoid legal?


                They're single axis.


                A: No. While it is true that a solenoid is a 1 degree of freedom assembly, it is also an electrical part. <RE06>.d disallows all other electronics (including solenoids)


                • #83
                  External Battery Pack for LED's

                  Originally posted by FTC5250
                  We would like to have a strip of LEDs on our robot for decoration.

                  According to rule <RE03> :
                  "Approved light sources may include an internal (as supplied by the manufacturer) battery. Additional
                  approved power sources are the use of a power port on the Core Power Distribution Module, a motor control
                  port on the Core Motor Controller Module, or a motor controller port on the Legacy HiTechnic
                  Motor Controller. "

                  We do not want to power it from our main battery through the Core Power Distribution Module because of the drain it would cause on the battery. Last year we hooked the lights to a separate 9v battery. The rule says that the lights may be powered by an internal (as supplied by the manufacturer) battery. These lights do not have one and are meant to be powered by a separate battery. We would like to confirm that this is still legal.

                  A: No. <RE03> lists the allowed power sources. An external battery pack is not a listed source and is not allowed.


                  • #84
                    Robot Motion During Initialization

                    Originally posted by FTC9794

                    Our team has a rack and pinion on our robot powered by a DC Motor. When the rack and pinion is all the way in, it presses a touch sensor. During the initialization of autonomous, is it legal to move the rack and pinion in all the way until it presses the touch sensor?

                    Thank you,
                    Team 9794

                    A: Yes. This type of initialization motion is allowed. Be sure to add a sticker warning of robot motion during initialization (see the game manual)


                    • #85
                      DC Computer Fan as Motor?

                      Originally posted by FTC9921
                      We want to use a 12V DC Computer Fan to blow away the debris.
                      If it is allowed, when the fan is plugged into the motor controller, does that count as a motor?

                      A: No. A 12V DC Computer Fan is not an allowed DC motor and may not be used on a robot.


                      • #86
                        LED's powered by Servo Controller Ports

                        Originally posted by FTC8681
                        We want to use a string of 6V LED Lights on our robot:

                        We wish to remove the battery and add the wire to the robot so it can be controlled in the program. It would still serve no functional purpose to the robot other than decoration.

                        According to rule <RE03> g:
                        "Approved light sources may include an internal (as supplied by the manufacturer) battery. Additional approved power sources are the use of a power port on the Core Power Distribution Module, a motor-control port on the Core Motor Controller Module, or a motor controller port on the Legacy HiTechnic Motor Controller."

                        Can we use a servo-control port on the Core Servo Controller Module instead? The rule implies that there are other approved power sources not listed.

                        In addition, if we were to use the supplied battery pack to power the LED strip and signaled the LED strip independently with the Core Servo Controller Module, would it be legal?


                        A1: No. LED's may not be connected to or powered by Servo Control Ports of any module.

                        A2: Without additional description, it is not possible to determine what "signaled the LED strip independently" means or whether the would be allowed under current rules.


                        • #87
                          USB Surge Protectors

                          Originally posted by FTC6081
                          As winter has arrived with drier air, we are seeing many robots experience static electricity discharges. Last year FIRST recommended installing a USB surge suppressor from l-com between the NXT and Samantha. We did this, and it seemed to help. Would this part be legal this year to install in the cable between the phone and the Power Distribution Module? If so we'll do some testing.

                          FTC 6081 i²r robotics

                          A: USB Surge Protectors are explicitly allowed by <RE05>.a


                          • #88
                            Mixing/Matching 12v DC Motors with Motor Controllers

                            Originally posted by FTC10877
                            Hello FIRST,

                            To clarify our previous question, we are using a Legacy Matrix system with a single 9.6V battery, two Matrix motor/servo controllers, and three Matrix 9.6V motors. We have been unable to source additional Matrix motors from Modern Robotics Inc., of any sort, and so we would like to use two or three of the AndyMark NeveRest (20,40,60) series of motors, with our Matrix module to drive additional mechanisms. We do not want to waste our money buying motors we cannot use, so we have not finished some of our mechanisms. The motors are rated at 12V, but we have heard from another team that they work fine on 9.6V - they simply run slower than they would at 12V, with no risk of damaging them. Is using NeveRest motors with the 9.6V Legacy a legal configuration?

                            Thank you.

                            A: After getting input from the manufacturers, 12v motors (of any of the allowed types) can be used with any of the Motor Controllers (Matrix, Legacy HiTechnic, Modern Robotics). Please note that the motor connectors may need to be changed. Care should be taken to fully understand the connections before modifying the motor connectors to minimize the chance of damage to the motors or controllers.

                            Teams should also be aware that the encoders that are built into several of the motors produce different counts per revolution and will likely make using the built-in PID control functionality difficult.


                            • #89
                              I2C I/O expanders?

                              Originally posted by FTC5206
                              Hi, we were wondering if the following type of device is legal per forum ruling #51, which explicitly allows an i2c multiplexer like this:
                              Are either of these (, or similar devices which expand an i2c port allowed to be connected to the CDIM in order to get more digital type pins?

                              FTC 5206, The Knights of Ni
                              A: No. The I2C multiplexor option was allowed to take care of the case where sensors have non-changeable i2c addresses. The allowance permits using multiple sensors of the same type.

                              The chips/boards referenced above are general purpose I/O expanders and fall under the category of "other electronics" and are prohibited by <RE06>.d


                              • #90
                                Red Dot Scopes Allowed?

                                Originally posted by FTC4997
                                Post #118 of the Mechanical thread ( states that the mentioned red dot scopes are illegal because they are not powered by the main robot battery. However, it does not say anything about the legality of them. Would a red dot scope (NOT a laser) that is powered by the main robot battery be legal? Thanks!

                                A: "Red Dot" scopes are not legal. Focused light sources are disallowed by <R06>.a