Hack Club
Background

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

Automatic Toilet Paper Folder

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.

ReadGood, The Single-Word Kindle

ReadGood allows you to read books how they were intended to be read - one word at a time. Featuring autoscroll and USB text uploads, nothing will stop you from enjoying your next short story.

Crazy Controllers

ARE YOU FINDING GAMES TO HARD? DO YOU STRUGGLE WITH ALL THOSE EXTRA KEYS? DO YOU WANNA FEEL SPIRITUALLY CONNECTED TO YOUR SCREEN? Well do we have the product for you with crazy controllers. Crazy controllers presents two unique ways of controlling the game.

Top 12

Spinny Snake 3D

A cool custom 3d game console that spins to face the user in the age old nostalgic classic game of snake!

Word Hunter

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

Choc3DP

A 3DP for the undercity hackathon in SF, that you guessed it prints chocolate. This printer encompasses the main problem of every programmer, we need more chocolate in our lives. Therefore, we invented (engineered) the Choc3DP, a revolutionary 3D printer that prints chocolate.

Peas Are Best Frozen

A snow peashooter inspired by the video game Plants vs. Zombies. Turn on the shooter and watch the peas fly out!

Blind Defusal

A two-player, cooperative "bomb defusal" game! One player is the "Operator" who has the physical device, and the other is the "Expert" who has the instruction manual but cannot see the device. Their goal is to disarm all the modules on the device before the timer runs out.

Shitty Meta Glasses

Shitty Meta Glasses that listens to your conversation and helps you insert tech jargon into your speech.

404: Drink Not Found - Vending Machine and Blot Tic-Tac-Toe

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.

cardboard box

4 direction dance pad on a cardboard box. will definitely not explode

Duck Off Doomscrolling (D.O.D)

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

See all 75 projects →

Made with ♡ by teenagers, for teenagers at Hack Club

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