I built an infrared speed sensor for my potato cannon.
More information: http://www.williamosman.com/2016/09/p...

Yes, I could have displayed mph instead of converting from fps.

Average acceleration: 328 g's
Acceleration time: 0.024 seconds
Projectile energy: 211 joules
Average power: 9250 watts ~ 12.4 horsepower

Music: http://www.newgrounds.com/audio/liste...

Lots of filming by: John Willner
http://www.johnwillner.com/