HTMAA 2025

Group project portion. We met as a group to compare embedded architectures, toolchains, and day‑to‑day workflows. We also opened a shared page on the architecture site titled Week 2, and everyone in our section contributed to it using git. Below are my notes distilled from that discussion, plus photos from my own kit build.

Two boards in Quentin Bolsee’s QPad kit

Our section had two board options that share the same form factor but target different microcontrollers: Seeed XIAO and ATSAMD21E.

  • XIAO version: the fast build. You mostly solder the module itself, the OLED screen, and two resistors. It can run C/C++ (Arduino) and also MicroPython—nice if you prefer Python—but you do need to be careful with runtime errors because you get fewer compile‑time guardrails than with C.
  • ATSAMD21E version: closer to a bare‑metal setup. It needs more supporting circuitry (power, LED, capacitors, resistors), so there’s more soldering and probing—but you see exactly what a minimal SAMD board requires to run.

USB connectors: tiny parts, big challenge

We had two SAMD variants due to sourcing: one with USB‑C, another with micro‑USB. Surprisingly, the connector footprint is the trickiest part of assembly. My take: micro‑USB felt harder because the metal shroud blocks access to some pads. I assembled the USB‑C version and still needed flux, fine tweezers, and patience.

Toolchains & workflow

  • Arduino IDE (C/C++): common path for both boards; quick to flash and great for early experiments.
  • MicroPython on XIAO: convenient REPL and scripting; watch for memory limits and runtime exceptions.
  • Git: we used a shared repo to document steps and compare setups; each commit shows the evolution of our boards and code.

Gallery

Team discussion
Group photo from our discussion and planning session.
Lecture slide 1
In the lab, closely watching how to solder—everything is so tiny.
Lecture slide 2
More observation of the soldering workflow and tips for handling small parts.
Lecture slide 3
Final notes before trying it ourselves.
SAMD board components
Finally getting hands‑on: so many, so tiny components.
Hot air rework
Using the hot‑air gun for reflow.
Assembled board
Assembly test complete: hello world succeeded!
Simple board install with friend
I also tried the simplest board install and took a photo with a friend.

Videos

Game 1 — A simple catching‑the‑ball scoring game.
Open code — ballgame.ino 
Loading…
Download ballgame.ino Folder: week03/ballgame/
Game 2 — With the help of ChatGPT, I design an electronic pet cat. Touch buttons change mood, health, etc. I even forgot which button did what—but it was fun!
Open code — catgame.ino 
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Download catgame.ino Folder: week03/catgame/

What I learned

  • Choosing a board is also choosing a workflow—XIAO is faster to start; SAMD teaches more about the base hardware.
  • Connectors can be the highest‑risk soldering step; anchor tabs matter as much as signal pins.
  • Keep a simple Blink and a serial echo sketch handy for smoke tests before bigger features.