Tell us about yourself!
Really cool to see this is still a thing! A few of my crazy friends (and a few enemies, too) and I made these bike from wrecked 20 inch bikes we found or bought for cheap. Mine had a coaster brake on the rear wheel that was actuated by a chain and cable running up to the handle bar pegs welded to the front fork. The front wheel was the rear wheel from a Schwinn stingray and it had a disk brake. I was probably the only rider who could actually stop without crashing into something! It's good to see there is still interest in downhill racing bikes after we did it 45 years ago! Great memories and absolute terror!
I could have sworn I posted this a long time ago... There is a typo in the lengths of the PVC pipe pieces. The long on should be 12 1/2 inches, not 17 1/2 inches. OP must have confused it with the 17 3/4" driven elements. Oops!
Harvesting Sound Energy From Passing Cars
I did this 15 years ago with a $5.00 cheapo webcam, a 486 motherboard, a 120MB HDD and Motion on Slackware. Worked great and sent me an email whenever it saw something. I still have it somewhere in the closet of ancient computers...