Robot Inspection and Build Rules - Electrical - Answer Thread

[Buckaroo Banzai]

Moto G 2nd Gen with Lollipop

Hi,

We have a Moto G 2nd Gen running Lollipop, and according to http://ftcforum.usfirst.org/showthread.php?5180-Can-t-downgrade-Moto-G-to-KitKat&p=20211&viewfull=1#post20211 on the FTC Technology Forum, this is approved by the GDC. Can we please get an official ruling on this in the official forum so that we can use it at a competition? Thanks!

A: Thanks to the friendly folks at Motorola, Moto G 2nd Gen phones with the latest version of Android (currently Lollipop) will work and are allowed for use in FTC robots and Drivers Stations.

[Buckaroo Banzai]

Linear Actuator

Are the servo actuators legal to use in FTC? URL follows:
https://www.servocity.com/html/25_lb...l#.VkOlPb_F9z_

A: No. The linear actuator linked above is not allowed. It is not a servo and is not a legal DC motor.

[Buckaroo Banzai]

New TETRIX Battery Legal?

Pitsco has a new battery. The 10-cell, 12-volt AA rechargeable pack is small and lightweight yet still packs a powerful punch. This 2,000 mAh NiMH pack features a built-in 15-amp replaceable fuse for safety - See more at: http://www.pitsco.com/TETRIX_MAX_12_....F2X9gZVG.dpuf

Is this battery legal for for FTC competitions?

A: No. The only legal batteries are listed in <RE03>.b

[Buckaroo Banzai]

Blue LED's On Robot

Just wondering if having blue LEDs on the robot will be an issue with the field sensors. That and because the team colors are blue and red, and if we're on red team would it be an issue? Pretty much just asking if blue LEDs are okay.

A: There is nothing in the rules that prohibits particular colors of LED's. If in the opinion of the inspectors or the referees, the LED's pose a risk of interference with another robot, they may require re-inspection and/or disallow the use of the LED's. (per Part 1 Section 5.3.1)

[Buckaroo Banzai]

Main Power Switch Requirements

We just had a quick question about the wiring of our robot -- We know that the Core Power Distribution Module has its own Power Switch on one side. Are we allowed to wire an external switch, such as the ones used last year, between the Battery and Power Distribution Module? We would then use this switch to turn the robot on and off, while the one built into the module stays permanently on. In our current electrical setup, the Power Distribution Module is not easily accessible, and that switch would not be easily turned off for an emergency power shut down on the field.

Thanks!
--
MOE 365 FTC

A: Yes. A separate Main Power Switch is strongly recommended. This is covered in <RG04>

[Buckaroo Banzai]

I2C Multiplexer Allowed?

Hi,

We wanted to use multiple Adafruit RGB Sensors on our robot. However, since they have a fixed I2C address, and each DIM only has a single I2C bus, a separate DIM would be required for each sensor, which is unreasonable and not feasible. We were wondering if the following I2C multiplexer would be allowed, so that multiple RGB sensors could be on one DIM: https://www.adafruit.com/products/2717 This thread has some more information: http://ftcforum.usfirst.org/showthre...it-RGB-Sensors

Thanks!

A: Yes. Simple I2C multiplexers, such as the one referenced, are allowed. They may only be connected to and powered from the I2C connections available on the Core Device Interface Module.

[Buckaroo Banzai]

External Battery for Video Camera Not Allowed

Can we use an external battery bank for the purpose of charging only a camera for non-functional post match entertainment?

A: No. Per <RE03>.f (internal, manufacturer supplied battery only)

[Buckaroo Banzai]

3rd Party Robot Code

Is it legal to use 3rd party libraries when programming our app? I'm thinking specifically of using OpenCV. But I'd like the general answer as well. Does it matter whether the 3rd party library is open source or not?

A: There is nothing in the rules that prohibits the used of 3rd party code/libraries.

[Buckaroo Banzai]

Bypass Core Power Distribution Module USB Hub?

As we continue to test our robot, we have found that the USB hub inside the Core Power Distribution module is very unreliable. We tried to get around this by using the USB hub usually connected to the driver phone to connect the game pads in the place of the core power distribution module. The CPDM is still being used to distribute power from the battery to the modules. Is it legal to use this USB hub in place of the Core Power Distribution Module?

A: No. Per <RE01>.b, the Robot Controller Android device USB interface may only connect to the Core Power Distribution Module. Standalone USB hubs are allowed, but only as connected to the USB hub ports on the Core Power Distribution Module (i.e. not directly to the Robot Controller Android Device)

[Buckaroo Banzai]

Recording Data on Robot Controller Android Device

During the autonomous period of our last meet, our robot had made an unexpected turn. This lead us to wonder if we are allowed to store our telemetry data during the match in order to review it afterwards. Are we allowed to store this data on the phone during the match? This will help us analyze our autonomous and to better understand why it makes certain decisions during a match.

A: There is nothing in the rules that prohibits the recording of data during a match on the Robot Controller Android Device.

[Buckaroo Banzai]

Additional Electronics

I.
Per <RE06>d, "Other electronics are not allowed." However, we are using ours as a form of manufactured sensor, which would be allowed under <RE06>b.i, where our Arduino is exclusively used for sensor purposes and is only connected to another sensor and the Core Device Interface Module.

If the Arduino would not be considered a manufactured sensor, why? It is not exclusively allowed or disallowed in the rules, and we used ours to great advantage last year through the HiTechnic SuperPro board. There seems to be no reason that the rules should have changed in this matter, since so many teams used this last year.

A comment earlier referenced that communication with an Arduino would require additional drivers, which may be an argument against it. However I already have a working prototype for communication with said Arduino through the I2C bus of the Core Device Interface Module, so it is definitely compatible for this year's game with a little work by the team, making the argument invalid.

II.
Is there any way to use 3.3v sensors with the Core Device Interface Module? Currently, my team only has access to 3.3v versions of the sensors that we require, however under <RE03>h, "External power adapters or voltage converters are not allowed." It would be cost prohibitive to buy new sensors when we already have the 3.3v sensors and voltage converters that are required for communication over I2C to the Core Device Interface Module.

A1: Arduino systems are not allowed per FTC Q&A Electronics Forum post #2 and post #18 (answers A3 & A4)

A2: We are not in a position to recommend solutions for this type of question. <RE05>.e.iii requires all power for allowed sensors to come directly from either the Core Device Interface or the Core Legacy Module.

[Buckaroo Banzai]

Laser Pointer Alignment Device

Can the kids use a small laser pointer to align the robot during during autonomous? We are looking to start at an angle to get to the Beacon repair zone. They would turn it off after setup and before they start the program.

Please let us know.

Team 9908

A: No. <G4> requires alignment devices to be made from legal components and to stay completely within the 18" cube starting configuration. Per <RE06>.a explicitly disallows focused light sources (including lasers).

[Buckaroo Banzai]

Removing Encoder From AndyMark Motor

Hello,

Under rule RE02, is removing the encoder from an otherwise legal Andymark motor such as AM2964A a legal modification?

We have a mechanism that is space constrained and we don't need the encoder, removing it makes the motor smaller. This does not impact safety and makes the motor "more usable" in this situation, so I'm hoping you say this is legal under RE02.

Thanks!

A: Yes. This is allowed. Be prepared to explain the modification to the robot inspectors

[Buckaroo Banzai]

Is Core Power Distribution Module Required?

Hello! We have been having USB problems with our CPDM interfacing with the phone and detecting controllers. To have a running robot, we switched out the CPMD for the Legacy Module, and daisy chained HiTechnic Motor and Servo Controllers to the battery with a switch. This configuration works perfectly. Would a configuration with a Legacy Module be legal if we cannot run our system via the CPMD?

Thanks,
FTC3737

A: No. This is not a legal configuration. Per <RE01>.b the Robot Controller USB connection must be to a CPDM. <RE03>.d requires that all powered modules be connected to the output ports of the CPDM.

[Buckaroo Banzai]

Robot Controller USB Cabling Options

Currently we use the Modern Robotics-supplied USB On-The-Go male to USB micro male cable to connect our on-robot phone to the core power distribution module. May we replace that single cable with following two cables strung together?
1) a USB On-The-Go to USB full-sized male cable connected to 2) a USB full-sized female to USB micro male cable.

We have had dead-robot disconnection problems at our first qualifier. The above would allow us to reduce the repetitions of plug and unplug cables into the phone and/or the power distribution module, potentially reducing wear and tear on those parts. More of the wear and tear would happen in plugging and unplugging the full-sized connectors in the middle of the double cable, which might be more durable or more easily replaced than the phone or the CPDM.

Thank you!

A: This is explicitly allowed by <RE05>.c "Either a Mini USB OTG (On-The-Go) Micro Cable or a Mini USB adapter and OTG (On-The-Go) Micro Cable is used to connect the Robot Controller Android device ..."