Speed Sensor Tube

This is an optical sensor to measure speed by time and distance. I use it for my experimental rail gun, specifically for auto tuning the coil timing to maximize speed. This is an experiment and will not result in a rail gun with notable projectile energy and is a mere physics experiment. The bore fits a 4mm projectile. Source code for testing is available at https://github.com/Cubernetik/SpeedSensor. In case anyone noticed that the final assembly has a black body whereas the other files are showing the part in red. Here's the thing. If you determine the pull down resistors for the optical sensor by using some black printed parts you might also want to print it black eventually. Turned out the infrared sensor very much liked that red color which defeated the purpose.