Community renewable energy hub
A hand-crank generator and feasibility study for turning everyday motion in community spaces — gym equipment, elevators, doors — into electricity people can see.
7–8 V, by handfiled underEnergy & thermalSustainability
The idea
Community centres and schools are full of motion that goes nowhere: people on exercise bikes, elevators running all day, doors opening and closing. Most people are also a long way from where their electricity comes from. Working with a community partner, our team looked at capturing some of that motion and, just as importantly, making the generation visible.
Why small and local
Centralised grids are vulnerable to extreme weather and equipment failure, and the usual backup is a fossil-fuel generator. Small hand-powered generators exist, but they’re built for emergencies, not for daily use in a public space. We wanted something people would use because it’s there and it’s interesting.
What we built
A hand-crank generator in three parts:
- The crank: a 3D-printed wheel and housing turning a generator motor. Printing let us iterate the housing quickly and keep rotation smooth.
- Regulation: a rectifier with diodes and capacitors turns the output into usable, storable DC.
- Feedback: indicators so users can see what they’re producing.
In testing it averaged about 7–8 V, enough to show that small-scale recovery works.
Would it scale?
Feasibility calculations put high-use systems like elevators and gym equipment at roughly 0.4–0.45 kWh a day each. That won’t run a building, but it offsets real consumption and makes the point visible. The design is modular, so piezoelectric, solar or small wind inputs could be added later.
Telling the story
Half the brief was education. We made a poster and an animated video for the community partner so visitors could understand what the generator does and why it matters.
Scraps from the build
