The spinner is pretty cheap. There are 2 metal fingers that touch a metal sleeve wrapped around the plastic. The sleeve goes all the way around in one area and 1/2 way around in the other area. So you get a 50% duty cycle signal as it rotates.

I've been looking at Red Line Racers, but they are generally too expensive, and the LBGP was cheaper. I did just pick up a broken RLR. Even if it's toast, we should be able to figure it out.

LBGP's sound is pretty grating. Another one where if I had been a parent back then, I would have regretted buying it for my kids.