Re: Small motor used as sensor
 

I would have agreed with you but not anymore.

I believe that the answer to the Tachometer question implied that R44 forbids all motors other that KOP motors and those specifically allowed by R44 (which reference the R43 exceptions).

Joe J.

Re: Small motor used as sensor
 

I have to disagree. With what I have read on the Q&As, and with the discussion here, I think that Joe is right on when saying that NO non-KOP motor may be used at all.

If it is a motor, not allowed. If it is listed and branded as a DC tachometer, then it is allowed.

It may sound like an odd statement, since some, if not all, DC tachs will have a motor/generator internally, but I think they want to not allow any non-KOP 'motor' from being on the robot in its purest form.

-Nate

Re: Small motor used as sensor
 

So you get a page of label paper for your inkjet printer

make a nice little label that says:

Kens Kustom Analog Tachometer
Model 2006F
Serial # 123456789
(not a motor)

and put it on a DC motor and Wallah! you have a tachometer.

This rule is really splitting hairs and getting lost in semantics. If a device with coils and magnets is not wired to a power source, then it is not functioning as a motor.

This reminds me of a black-powder kit I got for christmas one year. When assembled it was a black-powder pistol. But you must have a pistol permit to own a pistol. According to the manual that came with the kit, if you assemble it, but never fire it, then its not a pistol and you dont need a permit

but the first time you put black powder and a bullet, and fire the thing, then it instantly transforms into a pistol, and a permit is now required!

Re: Small motor used as sensor
 

Ken, I guess your idea would be OK if someone who qualified as a supplier could supply the motor (re-badged as a tachometer) to all teams as a COTS item.

My problem as an inpector would be how to tell a 'real' (!?) tachometer from a functionally identical device that was sold as a motor. Like Joe, I suspect this would be difficult.

Of course I agree with Ken and Joe that the rule is not technically sound; I also think it may be difficult to police.

Re: Small motor used as sensor
 

Let's not get too worked up about this "Motors can't be Tachs" rule. I am not ready to go storm the gates and get these people to see reason.

In actual fact, motors make a pretty lousy tachometers compared to how easy an alternative is on a FIRST robot. Basically all you need to do is get a Banner Sensor or an encoder or maybe even a reed switch mounted to the thing that was going to drive the motor/tachometer and then use the RC calculate speed by either counting pulses per given time or by timing each pulse (which is a piece of cake, given Kevin Watson's many fine examples).

I would argue that there is almost always a better solution to the tachometer problem than using a motor as a generator.

It is an unexpected rule interpretation, but it is one I think reasonable people can live with.

Joe J.