About to get wrecked by a fireball
Getting wrecked by a fireball
Getting wrecked by another fireball
Flex sensor + IMU glove

Inspiration

Tower defense is a great genre, but most of the action stays on a screen. We wanted to bring the battlefield into the physical world, so ARcher turns the player’s room into the map and their phone into a way to aim. Then we took the idea a step further with a custom glove that lets players draw and release a bow with their hand.

What it does

ARcher is an iPhone game where players scan a room and place a castle in augmented reality. They aim by pointing their phone and use the glove to draw and fire arrows at an enemy catapult and knights. Take out the catapult to win, and defend the castle from the knights or the siege is over.

How I built it

We built ARcher in Unity as a native iPhone AR game, using 3D assets for the castle, enemies, and battlefield. Players scan their room to place the castle, then use the phone’s camera to aim the bow. We connected a custom glove, built around a Seeed XIAO ESP32 and a flex sensor, to the Unity game with UDP over the phone’s hotspot.

Challenges I ran into

Connecting external custom hardware to a mobile game meant coordinating the glove’s sensor input, UDP messages, and Unity’s gameplay controls. The iPhone also needs local network permission to receive data from the glove. We’re testing the full ESP32-to-iPhone connection to make sure input arrives reliably during gameplay.

Accomplishments that I'm proud of

We built an AR tower-defense experience that places a playable castle in a real room. We integrated the glove input path into the Unity scene and added the iOS local network usage description. I’m proud that Siege AR brings together mobile AR, 3D game development, and a custom physical controller in one experience.

What I learned

I learned how software can connect digital experiences to the physical world through sensors, mobile devices, and real-time communication. That idea reaches beyond games: the same kinds of interactions could make software useful for training, education, accessibility, or hands-on tools. Building Siege AR gave me a better sense of how to combine hardware and software to make those experiences feel natural.

What's next for ARcher

We’re testing the glove connection on an actual iPhone and tuning how drawing and releasing feel in the game. Next, we want to refine the aiming and combat, and explore how the optional IMU data could add more natural control. Later, a VPS could support multiplayer coordination or shared game state.

Built With

esp32
flexsensor
unity

Submitted to

HackTX 2026
- Winner [Best Hardware Hack] Brick House

Created by

I built the bow glove, the wearable controller that replaces tapping the screen: you make a fist to draw the bow and open your hand to let the arrow go. I wired a flex sensor across a finger and an LSM6DSO32 motion sensor (accelerometer and gyroscope) to a Seeed XIAO ESP32 microcontroller, and built two gloves, one per player, each running off a USB power bank. I wrote the Arduino firmware, which calibrates each player's open hand and fist and saves it on the board. It turns finger bend into draw, release and cancel (a pull that's too weak doesn't fire), and measures draw power and bow tilt, with a recenter command to zero the aim. Each glove joins its player's phone hotspot and sends events to the game as small JSON messages over UDP. Every shot is numbered and every release is sent three times, so a dropped packet never loses or double-fires an arrow. Each glove also hosts its own test page with live sensor readings, and I wrote a Python script that sets up a new board in one command. On the game side, I connected the glove to our Unity AR app in C#. The glove takes over the bow automatically when it connects and hands control back to touch if it drops, arrows fire with the power the glove measured, and an on-screen status line shows the connection with buttons to recenter the aim or switch between aiming with the phone and with the glove's tilt.

Bilal Shihab
I worked on design of the firmware and hardware, wiring the hardware including the power solution, the glove controller assembly, as well as the interfacing software between the custom embedded system and the cell phone such as developing UDP software to enable communication between the controller and the cell phone

Jayanth B Damodaran
Krish Singh
Mohammad Rashid

ARcher