A while ago I built a trap for speed matching locomotives. That one suffered from erratic detection caused by weak infrared detectors. It also was track powered, requiring clip leads to an adjacent pair of rails.
Here's the start of V2. This one is LIPO battery powered. The top board is an Adafruit Feather Wing with a bright 128x32 OLED display. The bottom board, not visible in the photo, is an Adafruit Feather M4 Express. It has a built-in LIPO charger and a small prototyping area for mounting a couple resistors and a connector.
The original IR detectors were OK but the emitters far too weak. A pair of 5 mW red laser diodes solve that problem. The lasers really "hammer" the detectors for much faster responses that will be insensitive to ambient light.
The original trap was awkwardly long. I plan this one to be a 4 inch long tunnel with a 3 inch timing length.
Green light from the Feather board comes from a NeoPixel that serves as a battery level indicator.
Hundredths of a MPH is overkill but I wanted to be able to read small differences in speed step 1.
Now to build the tunnel, add the detectors, and mount the electronics. Hoping this one works well.
