In the face of growing energy bills globally, maker Amitabh Shrivastava has put an old treadmill to work — turning it into a run-powered generator capable of outputting a useful amount of power, while working on an even more powerful bike-based version.
“It’s mad easy to convert that disused old treadmill into a human-powered generator that can easily produce 25 watts or more,” Shrivastava claims of the project. “A spinoff project might be to convert the treadmill motor into a bicycle-powered generator, which can likely generate 100 watts easily.”
The aim of Shrivastava’s project is to show how old exercise equipment can be given a new purpose in life by not only providing opportunity for you to shed a few pounds or improve your fitness but to power real-world electronics at zero cost — and how the conversion can, he claims, be carried out “with minimal electronics experience and very basic tools.”
To prove the concept, Shrivastava has been adapting an old treadmill with built-in direct current (DC) motor — which, when spun by the user as they run on the treadmill, serves as a generator. An inverter and DC-DC converter complete the build-out, which proved enough to drive a TV — providing, that is, you don’t stop running. “I liked the concept even more when I realized that in a battery-less system if you stop running the TV would power off, and it would take a minute for it to boot back up,” the maker explains. “So, the device incentivizes keeping a steady pace.”
A more powerful bike-based version offers up to 100W of sustained power. (📷: Amitabh Shrivastava)
The treadmill version is entirely functional, but took rather more effort than expected to drive the TV. The solution: a bike-based version. “Since I am a road cyclist having done a couple [of] 100k rides, I know all too well that cycling is one of the most efficient forms of extracting power from humans,” Shrivastava says. “So, I took the treadmill motor out and made a bike trainer with the same electronics.”
Now, Shrivastava is concentrating on the hardware’s longevity: the higher output power of the bike-based generator proved too much for a pair of low-cost DC-DC converters used in the treadmill version, which burnt out; proposed solutions include using a more expensive converter, siphoning excess energy into a battery, or burning it off in an LED lighting strip or heater.
More details on the project, which targets the publication of a do-it-yourself guide anyone can follow, are available on Shrivastava’s Hackaday.io page.