Nobody likes power cords, and batteries always need recharging or replacing. What if your device could run on only the power it could gather together by itself? It would be able to run forever! Muah-hah-hah-hah. 

Hackaday’s Green Powered challenge asks you to show us your devices, contraptions, and hacks that can run on the power they can get out of the world around them. Whether it’s heat, light, vibration, or any other source of energy that your device gathers to keep running, we’d like to see it.

The top three entries will win $150 shopping sprees courtesy of the contest's sponsor, DigiKey, so get your entry in soon.

Honorable Mention Categories:

• Solar: In terms of self-powered anything, photovoltaic cells are probably the easiest way to go, but yet good light-harvesting designs aren’t exactly trivial either. Let’s see what you can run on just the sun. (Or even room lighting?) 
• Anything But PV: Harnessing the light is too easy for you, then? How about piezo-electric power or a heat generator? Show us your best self-powering projects that work even when it’s dark out.
• Least Power: Maybe the smartest way to make your project run forever is to just cut down on the juice. If your project can run on its own primarily because of clever energy savings, it’s eligible for this mention.
• Most Power: How much of a challenge is building a solar-powered desk calculator in 2026? How about pushing it to the other extreme? Let’s see how much power you can consume while still running without batteries or cords. Does your off-grid shack count here? Let’s see it!

A big thanks to Joe Kim for the amazing art!

Powered by DigiKey:

Rules:

• All entries must be powered by energy that they harvest from the environment themselves.  
• We want to learn from you. Document your project as well as you can so that we can follow along. 
• All entrants must agree to have the design published on Hackaday.
• Employees and contractors of DigiKey, Supply Frame, Siemens, Arduino, and their immediate family members are ineligible to win, but are still encouraged to enter.
• Rules and categories are subject to change and judges' decisions are final.

Examples:Need some inspiration? Here are some projects to check out that should get your ideas flowing:

• You can do a lot with the power of the sun. From running a small radio mesh repeater, to an entirely solar powered web server, there are certainly classic solar hacks. But if you don’t need all that much power, consider using a photodiode in place of that PV cell. Or go to the opposite extrene and let your solar cells take to the sky. 
• Heat is everywhere around us. If you need mechanical motion, the tried and true Sterling engine might be what you need. (While they’re usually precision devices, we love this one made of soda cans.) Or go straight from heat to electricity with the Seebeck effect, but note that it’s harder than you might expect. Here’s a simpler LED demo if you’d like.
• One of our favorite energy harvesters of all time is the Beverly clock, or its modern derivatives, that harvest the temperature and pressure differences in the ambient air across the day to keep running without winding.
• Does the humble crystal radio count? Of course! Whether your approach is back-to-the-basics or performance oriented, playing music with power harvested from the radio waves themselves is definitely green powered.
• We’ve always been tempted to try a piezoelectric-powered project, but the ridiculously high output impedance is a real challenge. That didn’t stop [b.kainka] from making a tiny, quiet radio transmitter from one. And check out this cutting-edge research into harvesting what we think of as static electricity. Can you do something with this?