Are we allowed to use old hard drives as counterweights to stabilise our robot?

[alipally11]

Hello, so we had some e-waste and we have some old hard drives that we duct taped together, it basically looks like a black brick. We also have some old dvd drives that i think we might use. So are we allowed to use a block of hard drives taped together(you can't see them) as weights?

[MrForbes]

I doubt it....there is a rule about motors, and you're only allowed to use hard drive motors if they are part of a COTS computer that is installed on your robot.

R18

[FrankJ]

Don't forget about accounting for cost on the BOM

[Tristan Lall]

Originally Posted by MrForbes

I doubt it....there is a rule about motors, and you're only allowed to use hard drive motors if they are part of a COTS computer that is installed on your robot.

It actually says "COTS computing device". Is a hard drive a computing device? It is usually used as a computer part, it has one or more microcontrollers in it, and it computes things. There's no rule that says it has to be operable. I'd give it the benefit of the doubt at inspection, because there's no clear guidance one way or another. (The Q&A may issue such guidance, in which case my position might change.)

Also, per Q315, if you strip the motor out, the motor is no longer part of the device, and thus the motor rules don't apply any longer.

[rich2202]

I'd be concerned about the tape

[EricH]

And, per Q389, Q315 answers the question.

[Brandon Zalinsky]

Could the magnets in those hard drives affect any of the other electrical components on the robot?

[Bill_B]

Too late now?

Head on down to the auto shop and have someone cut off as many of the appropriate lengths of leaf spring as you think you might need. Drill holes for mounting brackets and dangle as low and as far from your elevator as possible. There are also some equally dense but geometrically challenging metal parts in the auto shop. Remember if you cut them they're not COTS.

[Mongai]

It should not be a problem. While there ARE hard drive motors inside each hard drive, to my understanding of your post none of them are hooked up. R18 applies to hooked up motors.

[EricH]

Originally Posted by Mongai

It should not be a problem. While there ARE hard drive motors inside each hard drive, to my understanding of your post none of them are hooked up. R18 applies to hooked up motors.

R18 The only motors and actuators permitted on 2015 FRC ROBOTS include the following: [table of legal motors omitted for clarity]

Emphasis mine.

Would you mind explaining how you get R18 applying only to hooked up motors from that text, particularly given the bold portions? As an inspector, I'd be quite interested to know that.

[JohnFogarty]

Ask on the official FRC Q&A. You're just going to start an argument here on whether it will or will not be considered a motor on the robot. Which no one on this forum has the final say on anyway.

Are those old server hard drives? Those things are HEAVY.