Rube Goldberg Exercise Bike

Long story short, from the Washington Post:

Retired biomedical engineer Seth Goldstein, 80, whose motorized kinetic sculptures include "Why Knot," which repeatedly ties and unties a necktie; "Ro-Bow," which uses computer programming and mechanical rods to play tunes on a violin; and "Cram Guy," in which a robotic man speed-reads Cliffs Notes — his brain glowing red and pulsating — before he gives in to sleep deprivation — has completed what he calls his "wackiest" work yet: the "Rube Goldberg Exercise Bike," inspired by the iconic cartoonist and the fantastical gadgets he dreamed up.

[Seth Goldstein on his Rube Goldberg Exercise Bike]

By pedaling the stationary bike, Goldstein triggers a chain reaction that causes the machine to scratch his back, fan him, pour him a mug of water, and — if he really earns it — serve him a cookie.

The "Rube Goldberg Exercise Bike" took Goldstein two years to complete, with plenty of stops and starts along the way. One detour came a year ago, when he underwent open-heart surgery to have an artificial valve replaced. But he accelerated work on the project after the pandemic sent him and his wife into isolation in mid-March.

[Quarantining during the pandemic gave retired engineer Seth Goldstein time to complete the Rube Goldberg Exercise Bike, which provides its rider with cookies and back-scratches]

As Goldstein details his creation, he exudes an endearing sense of humor and infectious enthusiasm for the art. He recalls spending upward of six hours a day working on the sculpture, navigating plenty of trial and error. Even landing on Keebler Sandies as the right cookie took time, after his preferred choice, Oreos, proved too fragile to survive the system intact.

As Goldstein details his creation, he exudes an endearing sense of humor and infectious enthusiasm for the art. He recalls spending upward of six hours a day working on the sculpture, navigating plenty of trial and error. Even landing on Keebler Sandies as the right cookie took time, after his preferred choice, Oreos, proved too fragile to survive the system intact.

[A Keebler Sandies cookie rides up a conveyor belt before it is delivered to the pedaler powering the Rube Goldberg bike. The machine will also pour a mug of water]

All told, the device features five chains, six bands, and 10 timing belts transferring motion throughout the system. Each cycle finishes with the deflation of a balloon, which releases a barrier blocking the cookie. The baked good then falls onto a turntable before a conveyor belt brings it to Goldstein. As long as he keeps pedaling, the process repeats.