Robot Inspection and Build Rules - Electrical - Answer Thread

[Barry]

You'll find the answers to questions posted about Electrical Robot Components here.

[Leonard Hofstadter]

1. Will teams be allowed to use Arduinos / prototyping boards this year?
1b. If they are allowed, are there restrictions as to their use (interfacing with a sensor and reporting results back to the CDIM, or only decorative use such as quickly cycling LEDs to save power instead of just hooking all the LEDs directly to the battery and/or displaying an image on an LED matrix, which also requires rapid LED cycling).

The ability to incorporate Electrical Engineering more into the curriculum would be fantastic. It's understood the Core Device Interface Module can perform many of these functions, but for something which requires rapid updates, it would be highly preferable to offload this away from the phone and the devices running the robot.

Does <RE06> exclude supplementary controller boards (ex: Arduino) and/or Custom/DIY Sensors?

Would a digital volt meter be allowed on the robot? (example: http://www.powerwerx.com/batteries-c...ter-12vdc.html )

A: No, per <RE06>d. “Other electronics are not allowed.” The only allowed additional electronics by <RE06> are light sources (see also <RE03>g.), manufactured sensors and the HiTechnic NXT1060 multiplexor, and video recording devices (see also <RE03>f.); in addition, manufactured sensors must connect directly to the Core Device Interface Module or to the Core Legacy Module either directly or through a HiTechnic NTX1060 multiplexor and may not connect directly to robot power or to USB. Note that this rule also precludes the use of Legacy prototype boards, microcontroller boards, and custom sensors.

Communicating with additional electronics is likely to require drivers or other software support which is not available or which may not be compatible with the Robot Controller software used in this year's game. Although not allowed for this year's game, GDC will evaluate software and driver availability and compatibility to determine what additional electronics can be supported in future games.

[Leonard Hofstadter]

Are there provisions in the rules that allow us to generate custom sensors as was indicated when the new control system was being released? If so, what rule allows the use of momentary switches as limit switches and touch sensors? Would the same be used for potentiometers as rotational sensors?

A: No, per <RE06>b. custom sensors are not allowed; compatible sensors include manufactured sensors that are connected directly to the Core Device Interface Module or to the Core Legacy Module either directly or through a HiTechnic NTX1060 multiplexor.

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.

[Leonard Hofstadter]

Are LIDAR Sensors allowed?
They do use focused emitted light; but, so do the reflective light sensors.
I see some teams used them last year and were allowed if there power level was below a certain level

A: No, per <R06>a. LIDAR is both a laser and a focused/directed light source and is thus not allowed.

[Leonard Hofstadter]

Are motor controller power lines classified as "battery" or "motor" wires for AWG?

Does <RE03>d mean power for legacy motor controllers have to connect direct to the Power Control Module (no chaining)?
This would force a lot of home run wiring and making custom crimped Power Pole cables

A: Power connections to Core Devices must connect directly to the Core Power Distribution Module; this module acts as a power splitter for the battery thus these connections:

• must be connected directly to the Core Power Distribution Module per <RE05>e. and may not be chained
• should be considered Battery wires and per <RE05>g.i. must be 16 AWG or larger
• may use power splitters per <RE05>f.

[Leonard Hofstadter]

Are vision senors and/or using the phone camera allowed?
How does that fit with the <RE06> c?

A: Yes, you are free to use the phone camera as a sensor; other vision sensors are allowed if they are compatible manufactured sensors that are connected directly to the Core Device Interface Module or to the Core Legacy Module either directly or through a HiTechnic NTX1060 multiplexor. Note that per <RE06>c. “Video recording devices (GoPro or similar) are allowed providing they are used only for non-functional post match entertainment” and thus these devices may not be used as a sensor as they may not be connected to USB (<RE06>c.) or to power (<RE04>f.).

[Leonard Hofstadter]

When wiring this year's robots, will teams still need to have a separate Power switch connected between the battery and the Core Power Distribution module? Or will the power switch on the Distribution Module itself serve as the main power switch this year?

<RE03 c.> States the we are allowed to use a second power switch before the PDM. Are we allowed to use any type of Toggle or Rocker Switch, or does it need to match last years switch? When will the Wiring Guide be released?

A: Standalone power switches are optional but are strongly recommended; if used, per <RG04>a. the standalone power switch must be either “TETRIX (part #W39129) or MATRIX (part# 50-00300).”

FIRST strongly recommends using a standalone main power switch both to make it easy for field personnel to find as well as to protect robot wiring from interference. Per <RG04> and <RE03>c., you may use either a single standalone main power switch or the switch on the Core Power Distribution Module. Note, however, that using the switch on the Core Power Distribution Module and placing it so that it is readily accessible to field personnel may expose wiring connected to the Core Power Distribution Module to interference from other robots or field elements.

The FTC Wiring guide is available through [URL="http://www.usfirst.org/roboticsprograms/ftc/team-resources"] along with many other team resources; it is currently last year's wiring guide but will be updated soon with specific details for the new control system. Although some of the information is outdated (you should ignore references to the LEGO NXT and the Samantha module) the bulk of the guide will be useful in constructing a reliable robot.

The FIRST ResQ Robot Wiring Guide is now released! Get yours now at 2014-2016 Robot Wiring Guide.

[Leonard Hofstadter]

To prevent a total system shut down if their is an electrical issue during a match (current setup has one main fuse near battery), are distribution panels that allow each circuit to be on their own fuse allowed? example RIGrunner 4005 from Powerwerx: http://www.powerwerx.com/powerpole-p...nner-4005.html

By using this system, if there were a short in one of the circuits, than only that "branch" of sub circuits would be disabled. Allowing for the robot to still have some mobility and opportunity to continue to compete during a match.

According to the manual, power distribution splitters are allowed (<RE05>f). Just wanted to check that a "fused" splitter is allowed.

A: Yes, per <RE05>f. splitters with or without fuses are allowed.

Splitters may either be COTS/team constructed wire splitters (per <RE05>g. they must be at least 16 AWG) or purchased COTS passive power-distribution boxes such as the one that you have referenced; COTS passive power-distribution boxes may not contain switches or any other electronic components other than fuses. Splitters with fuses must have fuses configured so that they meet <RE03>e. such that all fuses are less than or equal to any fuses in line that are closer to the battery. Per manufacturer specification, the battery or Core Power Distribution Module must be fused with at most a 20 A fuse although you may use a fuse with a smaller current rating if desired.

[Wil Wheaton]

<RE04> Any compatible servo may be used.

1.Does this mean we can use any servo that meets the specs of modern robotics servo controller?

2.Is the HiTechnic servo controller still limited to only standard and quarter scale?

A1. Yes, any servo that meets the electrical specifications of the servo controller may be used. Make sure to pay attention to the stall current ratings. Additionally, <RE02> prohibits modification of the internals of the servos.
A2. There is no limit based on the physical sizes of the servos. Both the Legacy HiTechnic and newer Modern Robotics servo controllers have the same 5 amp total current limit for servos connected to the controllers.

[Wil Wheaton]

Are NXT/EV3 Lego motors allowed? The NXT sensors are explicitly allowed, but there is no mention of the motors that we can find.
If legal, would they count as a motor or a servo for the purpose of the 8 motor/12 servo limit?

A: No. NXT motors are not allowed.