Week 5 — Electronics Design

okay so for my final project i want a WebXR experience on my Quest 3. i’m also doing an independent study with my advisor (Takehiko Nagakura) to collect/clean Gaussian Splat files and turn them into shareable WebXR scenes. last week i compared different camera types and tried importing GS into a few engines, mainly PlayCanvas + SuperSplat, so i can share/view it. with SuperSplat’s viewer app i can literally export an .html and host it on our server (see: this link).

idea: the MagKey cassette → headset pulls a scene

for the course final i want to pair it with that study.So the user can just sit next to a table, put the headset on, place a tiny 3d-printed “MagKey Cassette” on a little platform, and the headset fetches a specific WebXR URL. kinda like a spatial Walkman, you can bring a place with you and jump in whenever you want.

sensor plan for this week

i asked chatgpt what’s a good tiny starter piece for the cassette idea for this week when I'm starting to learn about PCB for the first time. answer was: magnet pattern + Hall sensor. so: use a small magnet and a 3D hall sensor, detect presence over I²C, toggle an LED first. from the class inventory i found the Infineon TLE493D-A2B6 (Digi-Key p/n TLE493DA2B6HTSA1) and checked if it plays nice with the Seeed XIAO RP2040, and gpt said yes (it even told me how to do i simple breadboard check but i wasn't able to get there this week).

MCU: Seeed XIAO RP2040
Sensor: Infineon TLE493D-A2B6 (3D Hall, I²C)
Library: fabcloud KiCad library
Firmware: Arduino IDE

parts list i used:

XIAO RP2040
TLE493D-A2B6 (or breakout)
2× 4.7 kΩ I²C pull-ups
1× LED + 1 kΩ series resistor
1× 0.1 µF decoupling cap (VDD↔GND at the sensor)
small neodymium magnet (3–5 mm)

Net labels that actually made things click

The wild helpful part was gpt handing me a set of net labels with what each does. made wiring the schematic way less scary.

GPT suggested net labels sketch — Fig. 1 — GPT’s net label sketch i followed.

Net naming table for KiCad — Fig. 2 — the net naming table i used while drawing the schematic.

Board setup

Just followed last thursday’s recitation and set the rules.

Clearance grid example — Fig. 4 — spacing check: 100 mils, 50 mils, 25 mils.

Errors → Fix

Following the recitation tutorial, I ran Design Rule Check before I exported the file and it complained. Turned out i missed a tiny internal GND connection on the hall sensor footprint. Those are small details that were really hard to catch without a the DRC. So I just zoomed in, patched it, and re-ran DRC, it was clean.

error found — Fig. 7 — DRC error complained.

DRC error screenshot — Fig. 8 — DRC error spotted.

Fixing the missing ground connection — Fig. 9 — DRC error fixed.

final schematic + pcb

Final schematic editor view — Fig. 10 — schematic editor (final).

Final PCB layout — Fig. 11 — pcb layout (final).

exports → gerber2img preview

exported the needed layers per recitation, then tossed them into gerber2img to sanity-check.

Export settings — Fig. 12 — export settings.

Generated Gerbers list — Fig. 13 — generated Gerbers.

Gerber2img result overview — Fig. 14 — gerber2img preview #1.

Gerber2img traces and outline — Fig. 15 — gerber2img preview #2.

Final preview — Fig. 16 — final preview from the generator.

High-res traces image — Fig. 17 — full-res traces.