4-day Hardware Hackathon
July 11-14, 2025 @ GitHub HQ
Undercity was a 4-day hardware hackathon @ GitHub HQ that happened July 11-14, 2025! It was hosted by Hack Club, for teenagers worldwide.
To get invited to Undercity, teens had to build a project through Highway first.
166 teen makers ・ 75 total projects ・ 19 countries ・ 72 hours of magic ・ ∞ memories made
Watch the Undercity documentary video!
...and some videos made by teens who came!
Check out these projects made at Undercity!
Top 3
Do you use a toilet? Do you do the number 2? Then the Automatic Toilet Paper Folder is just for you. It doesn't just dispense toilet paper for you but folds it too, greatly simplifying toilet usage. It can be especially helpful for people with limited dexterity or those who simply want to get back to doing their real business.
Top 12
A XY gantry system to play the GamePigeon game Word Hunt. A Camera module takes a picture of the Word Hunt board. It then uses an algorithm to read and process the letters on the screen. The Python script then uses a dictionary file to generate the best words and their swipe paths, which is sent to the XY gantry system with two stepper motors holding an Apple Pencil to play the game. On our best attempt (so far), it scored 23,800, which is much higher than the average score
Created at HackClub's undercity, Drink Not Found is a system where you play Tic-Tac-Toe using a drawing machine against AI-buddy Auto (credit: Paolo). If you win, you can pick a drink from the vending machine, and randomly get any drink except that one. Also, you contribute to a unique mosaic.
Duck off Doomscrolling is a fun way to quit destructive/disruptive/depressing social media! Basically it is a duck that will sit on your desk while you work and squirt water on you if you open doom scrolling apps such as Instagram Reels, Youtube shorts, or X. LETS QUIT DOOMSCROLLING :D
Made with ♡ by teenagers, for teenagers at Hack Club
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