Found an arc lighter kit lately, so I built one from it. then I used it to trigger an alcohol cannon built from an syringe. Then a reed relay is used to interface this kit with Arduino, so some more interesting projects can be built with a microprocessor like Arduino. In this video, an Ultrasonice sensor is used to sense a Cocacola can and fire upon it after some warning delay.
The original idea was to use a servo to rotate the ultrasonic sensor and syringe, sort of like a scanning radar, but the ultrasonice sensor does not have enough resolution to make it very accurate. Maybe a LiDAR module is better.
Other interesting projects idea might be an alcohol rocket; light up gas for (room) heating control; etc, etc, all under control of an Arduino
For those in China who can not access Youtube, you can watch the video here