DiodeAR

Hardware aint hard
Unity
Idk

Inspiration

Hardware is intimidating for new engineers: it’s unclear what to buy or build, and even small mistakes like miswiring can lead to hours of debugging, often killing motivation. We set out to remove these barriers. That’s why we built DiodeAR.

What It Does

DiodeAR is an AR circuit simulator for the Meta Quest 3. It places a virtual Arduino Uno, breadboard, and a full library of components—LEDs, resistors, capacitors, transistors, and more—directly into your physical space.

You grab components with your right hand, wire them with your left, and receive real-time feedback as soon as a circuit is complete. No soldering, no damaged components, no fear.

How We Built It

DiodeAR runs on Meta Quest 3 using full-color passthrough AR, built in Unity 6 with the Universal Render Pipeline.

The interaction model is split across both hands:

Right hand: grab and reposition low-poly 3D components (Arduino Uno, resistors, LEDs, capacitors) using OVR hand tracking and pinch detection
Left hand: draw wires by pinching terminals, dragging, and releasing to connect

Each component has typed terminals (anode/cathode, VCC/GND) that snap together into a live electrical node graph.

Under the hood:

Each terminal owns a node ID
Connected terminals share the same ID (like a SPICE netlist)
On wire changes, a connectivity solver runs BFS from voltage sources through the graph
If a valid path exists from VCC to GND (e.g., through an LED), the circuit is considered live and updates instantly

Rendering:

Custom wire renderer using stretched cylinder primitives with URP Lit materials for correct single-pass stereo rendering
Physical undo button (orange box in AR) allows wire removal via right-hand pinch

Challenges We Ran Into

SPICE Simulation in IL2CPP

SpiceSharp relies on reflection and [ParameterName] attributes
Unity’s IL2CPP strips untraced methods, silently breaking the diode model
Result: simulator ran but produced incorrect outputs
Root cause traced to the linker after extensive debugging

Hand Tracking Precision

Pinch midpoint drifts near small objects
Conflict between terminal snap radius and wire deletion radius
Large radius → accidental deletions
Small radius → unreliable connections
Required real-device iteration (simulator didn’t reflect real jitter)

Rendering in Passthrough AR

Required URP-specific materials for correct depth, stereo, and transparency
Unity’s default CreatePrimitive() uses incompatible shaders, breaking stereo instancing

Accomplishments We're Proud Of

Built a complete AR hardware sandbox in a single hackathon
Enabled real-world spatial circuit building with real-time feedback—no traditional tools required
Designed intuitive interaction: right hand for placement, left hand for wiring
Implemented a fully functional node graph solver supporting:
- Series circuits
- Undo/redo
- Ground re-pinning after wire deletion

What We Learned

IL2CPP’s interaction with reflection-heavy libraries can cause subtle, hardware-only bugs
Spatial UI design is highly non-intuitive—thresholds must be tuned through real usage
Effective AR augments reality rather than replacing it

DiodeAR doesn’t replace a breadboard—it removes the fear of using one.

What's Next for DiodeAR

Arduino CPU Emulator

Move from static 5V source to full code execution
Upload sketches and simulate real microcontroller behavior:
- GPIO signals
- PWM dimming
- Sensor-driven logic
Tight coupling between:
- CPU emulator (drives voltages)
- Circuit solver (propagates signals)
- AR scene (visual feedback)