Miscellaneous Robot Electrical Parts and Materials

[Pierluigi Collina]

Subject: I2C Controlled LED displays

Question:
Game Manual Part 1, rule <RE13> states that functional and/or decorative light sources are allowed, given constraints including the following:
• The light source is not focused
• The light source is controlled by compatible ports on the REV Expansion/Control Hub and may be powered by I2C sensor ports (among other ports enumerated in the game rule)

Given these known constraints, would a (non user-programmable) COTS LCD or OLED display, powered legally and controlled by an I2C port on the REV Expansion/Control Hub, be an allowed robot component, given that it is a functional light source and meets the criteria established in Game Manual 1? The light emission from this type of light source would be akin to that of the Robot Controller phone.

An example of such a component would be this display from Adafruit: https://www.adafruit.com/product/931

(This question is intentionally separate from previous questions asking about legality of an HDMI display, knowing that the HDMI display is classified under the category of “Additional Electronics” given its additional complexity and the lack of a legal means of data transfer given its reliance on the Control Hub’s HDMI port.)

Answer: LCD Display - no, LED Display - yes. At a base level, an array of LEDs controlled via I2C is no different than a string of LEDs controlled via I2C. Current rules would place LCD modules into other electronics.

[Pierluigi Collina]

Subject: Grounding Signal Cables to Robot Frame

Question: Is grounding a shielded cable's drain wire to the robot frame legal?

Answer: No. The only allowed electrical connection to the robot frame is via the REV Resistive Grounding Strap (per <RE15>.k)

[Pierluigi Collina]

Subject: REV Grounding Strap

Question: Assuming the resistor stays intact, is lengthening, shortening, switching out either the XT30 or ring terminal on, or changing out the cable on the REV grounding strap legal?

Answer: No. No modifications to the REV grounding strap are allowed.

[Pierluigi Collina]

Subject: HDMI Monitor in Robot

Question: Is it legal to have an HDMI monitor connected to the Control Hub?

Answer: No. HDMI monitors would fall under <RE18> Additional Electronics.

[Pierluigi Collina]

Subject: GoBILDA Battery

Question: Is the GoBLIDA battery allowed this season? It is just a different physical layout to the same battery cells used in the Matrix and Rev batteries, so it does not provide any capacity or power benefits.

Answer: No. The only batteries that are allowed for use are listed in <RE03>

[Pierluigi Collina]

Subject: COTS LED Module
Question: COTS LED Modules with integrated ATTiny85 microcontroller were approved for 19/20 completion season (original post). Could you confirm if this decision is applicable for 20/21 competition season?

Answer: As long as the processor in the LED module is not user programmable, the LED module would be allowed as long as it meet the requirements in RE13

[Pierluigi Collina]

Subject: Blinkin LED Driver

Question: Could you confirm if Blinkin LED Driver is legal for Ultimate Goal season (and explain if possible)? Latest FTC SDK includes Blinkin Driver sample OpMode which implies that Blinkin LED Driver is legal, but explanation for legality of USB/SPI bridge appear to rule Blinkin out of compliance since it is not connected to the components listed in <RE12>b.

Answer: RE12.b allows light sources controlled by compatible ports of the REV Expansion Hub or REV Control Hub. The Blinkin LED Driver connects to and is controlled by a servo port and is included in the sources allowed by RE12.b

[Pierluigi Collina]

Subject: USB Control of LED strip

Question: Our team would like to add controllable RBG light strip for aesthetics and for signaling purposes in TeleOp and Autonomous. Adafruit's DotStar LED strips (https://www.adafruit.com/product/2238) were permitted in the past with I2C to SPI bridge. Can we use USB to SPI bridge (https://www.adafruit.com/product/2264) chip to connect RGB strip to powered USB hub? The board is not user programmable and available in COTS package (datasheet https://www.ftdichip.com/Support/Doc.../DS_FT232H.pdf).

Answer: In short, No. An I2C to SPI bridge would be acceptable. The USB to SPI bridge to control the LEDs violates RE13.c

[Pierluigi Collina]

Subject: Robot Controller Phone LED Light

Question: Game manual part 1 <RE13> neither explicitly allows nor disallows use of the camera flashlight. It can be helpful with computer vision tasks. Rulings regarding its use in prior seasons have been:

2017-18 -- allowed
2018-19 -- initially disallowed, then allowed
2019-20 -- allowed

Will use of the camera flashlight be allowed for the 2020-21 season?

Thank you.

Answer: Yes, the LED built in to the robot controller phone may be used as a light source.

[Pierluigi Collina]

Subject: Interconnect Only PCB

Question: Hello!

I believe this is allowed based on previously asked questions, but wanted to make sure. Is a custom PCB that has no electrical components on it besides connectors that is used strictly to connect things like motors, encoder, sensors, etc. allowed?

A similar question is asked here: https://www.firstinspires.org/sites/...-questions.pdf
(use ctrl + f and type "pcb" to find it)

Answer: Yes. Be sure to have a circuit diagram for the PCB and be prepared to discuss/describe/explain the PCB to inspectors at your events (if attending Traditional Events)

[Billie Jean]

Answers to questions about Miscellaneous Robot Electrical Parts and Materials.