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Electronics Recommendations for Next Year

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  • Electronics Recommendations for Next Year

    FTC Staff,

    I would like to see the following recommendations considered for next year. Please note that I am not including the use of Arduino/RaspberryPi for middle men between the robot, sensors, and components as other teams are hoping for, but I am trying to expand the resources teams have available (and in most cases at a lower cost).

    DECORATIVE LIGHT SOURCES - Additional Power Sources
    Allow team provided battery to supply power to decorative light sources such as a single 9V, 4AA, 4AA, etc.
    This is currently not allowed by <RE03.g> and <RE05.e.i>.

    DECORATIVE LIGHT SOURCES - Voltage Converter
    Allow the use of a voltage converter from the PDM Power Output to decorative light sources
    <RE03.h> Does not allow voltage converters.

    OTHER ELECTRONICS - Pull Up and Pull Down Resistors, current limiting resistors
    Recommend allowing the use of pull-up and pull-down resistors so that teams can wire limit switches so that they can be used via the CDIM as a sensor and allow LEDs to be used that require different resistors to function properly (again powered from the CDIM).
    This is currently not allowed by <RE06d>.

    INCREASE NUMBER OF SENSORS AVAILABLE - Voltage Convertor and Other Electronics
    Many of the sensors that are on the market operate at 3.3V. In order to use these sensors with the current system one must install a level logic convertor similar to https://www.adafruit.com/products/757 and https://www.adafruit.com/products/395 or build their own voltagle divider.
    Recommend allowing level convertors similar to those I have linked so that teams can have access to the full spectrum of available low cost sensors.
    This is currently not allowed by <RE03.h> and <RE06.d>.

    ALLOW USE OF MULTIPLEXERS - Other Electronics
    Using limit switches connected to the binary ports on the CDIM. Multiple limit switch binary signals can be processed by the same analog port on the CDIM if multiplexers were allowed. The only allowed multiplexer is the HiTechnic Touch Sensor Multiplexer. However, teams could wire up 4 limit switches and a multiplexer to the CDIM for less than it costs for a single Touch Sensor. Yes, I know that a team would have to write their own driver library for their custom mux'd limit switch, but there are many examples available and I know that several of the frequent contributors to the forums would probably be happy to help.
    This is currently not allowed by <RE06.d>.

    ALLOW CUSTOM SENSOR LOGIC CIRCUITRY - Other Electronics
    Recommend allowing teams to develop their own custom sensor circuitry by allowing the use of basic electronic components (potentiometers, diodes, capacitors, resistors, switches, etc.) so that some of the logic is handled by the circuitry before it is passed to the CDIM. This could be as simple as allowing us to use the HiTechnic Prototyping Boards (or other prototyping solutions).
    This is currently not allowed by <RE06.d>.

    MOTORS
    Sometimes a robot doesn't need a large motor to accomplish movement on a given subsystem. Allowing use of other 12V Gear Motors with such as http://www.jameco.com/webapp/wcs/sto...0001_253534_-1 and http://www.lynxmotion.com/p-93-gear-...6mm-shaft.aspx could allow teams to optimize the design of their robots.
    Recommend changing the allowed motors so that the list reflects a Voltage and Current limit (Similar to the current servo limits) instead of forcing teams to purchase motors from a sole source (yes, I know there are 3-1/2 vendors, but 2 of the 3 vendors ran out of motors several times during the competition period).
    This would require a change to rule <RE04>.

    SOFTWARE/SDK UPDATES - Reasonable time limit to update versions
    Rule <RS03> requires teams to use the most recent version of the SDK at competitions. However, sometimes it is not as simple as downloading the new libraries and building the new controller applications. I recommend that a minimum of a 7-10 day grace period be allowed from SDK revisions until the SDK revision is required to be used by teams. Personally, I would be very hesitant to change libraries without significant and thorough testing on our competition robot.


    Overall, my concern is that most of the electrical and electronic components come from at most 3 sources. Even allowing "Sensors from any manufacturer" in the rules <RE06.b.i> limited teams to very few of the current sensors that are on the market as we were not allowed to install any electronic components between the sensor and CDIM (i.e., resistors, level limiters, mux's, etc.). This was what many of us were hoping to be allowed after watching the new technology presentation at the end of last season.

    Very respectfully,

    Team 8881
    Pirates of the Pacific

  • #2
    Originally posted by FTC8881 View Post
    FTC Staff,


    OTHER ELECTRONICS - Pull Up and Pull Down Resistors, current limiting resistors
    Recommend allowing the use of pull-up and pull-down resistors so that teams can wire limit switches so that they can be used via the CDIM as a sensor and allow LEDs to be used that require different resistors to function properly (again powered from the CDIM).
    This is currently not allowed by <RE06d>.

    Very respectfully,

    Team 8881
    Pirates of the Pacific
    Hmm, was there a ruling in the game forums on external pullups? There's no
    internal pullup on the CDIM, and so, as you state, limit switches don't work without
    external circuitry. However I didn't read <RE06d> as strictly as you. We don't
    currently have limit switches on the robot, but they've been very common in
    the past and we were considering adding a few.

    Comment


    • #3
      Originally posted by skatefriday View Post
      Hmm, was there a ruling in the game forums on external pullups?
      http://ftcforum.usfirst.org/showthre...ll=1#post18114

      Comment


      • #4
        But, Post 3 in the same forum also contradicts:

        http://ftcforum.usfirst.org/showthre...-Answer-Thread

        Simple manufactured devices may be considered sensors as long as they are compatible with the Core Device Interface Module; thus a simple switch is an allowed sensor. Note that per <RE06>d. you may not add any other electronics to the switch. If required, per <RE05>g. “sensor wires and their connectors may be extended, modified, custom made, or COTS” to connect to the Core Device Interface Module.

        This is why I want to specifically add external pullups.

        Comment


        • #5
          Originally posted by FTC8881 View Post
          But, Post 3 in the same forum also contradicts:

          http://ftcforum.usfirst.org/showthre...-Answer-Thread

          Simple manufactured devices may be considered sensors as long as they are compatible with the Core Device Interface Module; thus a simple switch is an allowed sensor. Note that per <RE06>d. you may not add any other electronics to the switch. If required, per <RE05>g. “sensor wires and their connectors may be extended, modified, custom made, or COTS” to connect to the Core Device Interface Module.

          This is why I want to specifically add external pullups.
          Yeah, that's confusing and it would be nice to have a clarification.

          > A2: Yes. Passive components, as required by sensor manufacturers are allowed.

          My simple manufactured switch requires a pullup, the pullup is passive. Is it allowed? :-)

          I'd like to see V2 of the CDIM include configurable internal pullups on the DIO ports.

          That would make the question moot.

          Comment


          • #6
            skatefriday,

            1) I concur regarding external supplies for decorative light sources.

            2) I agree also re Arduinos, etc; most of the sonar distance sensors we could have used this year (ultimately we weren't able to) need something like an Arduino to handle the real-time processing.

            3) Agree as to pull-ups, etc.

            4) As to multiplexers, there was a GDC ruling from earthquake that allowed at least simple I2C multiplexors to be used.

            See: Thread: Robot Inspection and Build Rules - Electrical - Answer Thread - Post #50
            https://www.adafruit.com/products/2717
            http://ftcforum.usfirst.org/showthre...it-RGB-Sensors

            Thanks,

            Martin Haeberli
            (de-)Mentor, FTC 7593, TigerBots

            Comment

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