Commercial Off the Shelf Components - Answers

[Luke Skywalker]

Rack and Pinion

Q: Is the TETRIX Max Rack and Pinion kit an allowed part this year under the exception to <RM02>?
https://www.pitsco.com/TETRIX-Rack-a...ear-Slide-Pack

A: Yes, Rack and Pinion kits are legal COTS parts.

[Luke Skywalker]

Lander Support Bracket

Q: Are the lander support brackets(the ones used on the lander for hanging) legal to be used on the robot? https://www.andymark.com/products/la...upport-bracket

A: Yes, this is a legal COTS part.

[Luke Skywalker]

Sticky Material

Q:Would we be allowed to use a mechanism with a sticky substance (like duct tape) to aid in gathering minerals? The adhesive does not leave a residue on the minerals or floor tiles, nor would it be strong enough to stick to or entangle another robot.

Thanks for your consideration!

A: Using a sticky substance in contact with a Scoring Element or Field Element is legal providing there is absolutely no residue. Teams using such a substance may have to demonstrate to the Robot Inspector or Referee that no residue remains on the contacted surface. If this cannot be demonstrated satisfactorily, the team will have to remove the substance/mechanism. Note that Duct Tape is known to leave a sticky residue https://www.wikihow.com/Remove-Duct-Tape-Residue so this would not be a legal material to use in this situation.

[Luke Skywalker]

Right Angle Gearbox

Q: We are removing right angle gear box from this driver and using it on our robot. Is this legal to use?

https://www.dewalt.com/products/acce...hment/dwara100

A: Rule <RM02> allows for the use of single speed gearboxes, therefore this gearbox is a legal COTS.

[Luke Skywalker]

Carabiner

A: is this COTS part, known as King Frog Cable carabiner, legal for FTC.

https://www.kong.it/en/2-products/it...p98-frog-cable
It has a single degree of freedom (two latches rotate on a single pin) and a single purpose, which is closure around a rope or other solid object that is inserted into the latch area.

The closure force is provided by pushing the latches against a solid object. It has no spring or other auto closure mechanism. It

A: Yes this is a legal COTS part.

[Luke Skywalker]

Gearbox Modification

Q: I know we can replace a motor's gearbox, but is it legal to modify the gearbox that comes on a motor? <RE15> says that (electronics) "may not be modified internally". However in the box underneath it says "Replacing gearboxes and/or changing gears" is an example of allowed modifications.

A: Yes, replacing gears is a legal modification.

[Luke Skywalker]

[QUOTE=FTC9794;n70734]
Dashpot

Q: Is a dashpot a legal mechanism?[/QUOTE]

A: No, a dashpot, like a shock absorber, works by forcing a fluid (air, oil) through a small orifice. This results in pressurizing the fluid, which is illegal per Rule < RG01.J,K>

[Luke Skywalker]

Wide Angle Lens

Q: Is it legal to use this lens with the camera on our phone?

https://www.amazon.com/Compatible-Se.../dp/B06XY4MFSX

A: Yes, providing it is not used to focus the light emitting (flash) from the phone.

[Luke Skywalker]

[QUOTE=FTC6378;n72534]
Suction Cups

Q1: Could a suction cup be used to pick up a mineral? It doesn't seem to be a "closed gas device", unless it becomes one when it is sealed against the mineral.

Q2: In a related question, could we make our own air blower to create a low pressure in a tube to lift minerals? Again, it wouldn't be a closed system, but the pressure differential would be present due to the air being blown out of the tube.

Thanks for your guidance![/QUOTE]

A1: Yes, providing the suction cup does not damage the Minerals

A2: Yes, providing the exhaust blower air is not constrained in any way that results in an increase in pressure.

[Luke Skywalker]

Shocks
Q: FTC team 13023 would like to use Robot Shocks from Servocity on our 2018 robot.

https://www.servocity.com/aluminum-robot-shocks

Robot Shock will be kept empty with no air compression and shock oil (all oil will be drained (emptied) from the piston). This part will be used only as a spring guide on a free wheel, and not as a shock absorber.

P.S. We have read the Game Manual and forum posts related to Build Rules.

A: A commercial shock that has been modified to insure that there is no possibility of compressing air or oil, the mechanism is a legal COTS. Be aware that at Robot Inspection your team will most likely have to demonstrate to the Inspector that this device is not a "shock" but simply a guided spring.

[Luke Skywalker]

Bungee Cords

Q: Is it legal to use using bungee cords (1 or 2) that stays attached to the robot thoughout the game?
https://www.amazon.com/kitchentoolz-...ds=bungee+cord&psc=1

A; Yes, bungee cords are considered springs. which are allowed in <RM01>.

[Luke Skywalker]

4 Axis Phone Mount

Q: Is 4-axis, 360 degree magnetic phone mount legal? See the attached link for example.
https://www.amazon.com/dp/B00I608BJ8..._t4_B07BZPFZDZ

Thanks.
FTC 13197 - TESLAS

A: No, Rule <RM02> limits COTS parts to one degree of freedom.

[Luke Skywalker]

Friction Damper
Q1: This question is coming from me as a hardware inspector. I'd like to get an official ruling.

There are COTS "rotational dampers" (which is an incorrect name since they don't actually dampen motion like a shock absorber) that are nothing but friction a hard-to-turn gear that helps reduce jittery motion. This devices contain no liquids. (There are some that do, and those are clearly illegal.) These devices only have one degree of freedom (rotational) which would seem to make them legal -- similar to a rusty hinge pin. The fact they are 1 degree of freedom, contain no liquids, and are a form of hinge seems to imply they would be legal.

Q2: On a similar note, I saw a team with a spring-loaded gate hinge. My ruling on that is that it is illegal because it is COTS with two degrees of freedom -- one for the plane being hinged and one for the rotational motion of the spring resisting that motion. (Hinges are legal and springs are legal, so a team that builds the spring loaded hinge would be legal.)

Any official confirmation on these?

A1: A friction damper that relies solely on friction, using no hydraulic dampening is legal.

A2: In the past we have allowed spring loaded linear rods. The spring loaded hinge is the same type of part just in a rotary motion instead of a linear motion. These are legal components.

[Luke Skywalker]

Worm Gearbox

Q: Are worm gear gearboxes like this one legal?
It's a single speed, back-drivable gearbox.
https://www.igus.com/product/1404

A: Yes, per Rule <RM02> single speed gearboxes are legal.