This coil launcher is based on a disposable camera flash system. It uses the charging system from one camera plus the the flash capacitors from four cameras. The coil is 200 turns in 10 layers wrapped around a glass tube with a 3mm inside diameter. The projectile is a 2.5mm diameter nail. It certainly isn’t as high powered as some of the systems we’ve featured, but firing at 20-25m/s it can still be dangerous.