I know you said single car timer, but seeing this brings back my Bit Char-g/zz/micro sizer days.
We built a timer with laser pointers, that would time 4 cars. You had 4 lasers in one stack. Each micro car had a guitar string sticking up, with a "flag" of sorts at each level of the laser.
Only the car passing the laser at the correct height, would trigger that timer.
Laser wouldn't be broke enough with the thin guitar string.
Sold it long ago, don't remember exactly how it was done, there might be tuts still online somewhere. Could in theory work for slots if you didn't mind a short guitar string with a small flag.
We built a timer with laser pointers, that would time 4 cars. You had 4 lasers in one stack. Each micro car had a guitar string sticking up, with a "flag" of sorts at each level of the laser.
Only the car passing the laser at the correct height, would trigger that timer.
Laser wouldn't be broke enough with the thin guitar string.
Sold it long ago, don't remember exactly how it was done, there might be tuts still online somewhere. Could in theory work for slots if you didn't mind a short guitar string with a small flag.