'll uno' Arduino Serial Monitor

'll uno' Arduino Serial Monitor | Generated by AI

Home 2026.07

Here’s a comprehensive summary of everything done in this session:

Session Summary: `ll uno` subcommand — Arduino UNO serial monitor

Project context

ll is a Rust CLI tool (/home/xiaoxin/projects/ll/) with a ratatui TUI interface. It already had info (system info), gcloud, and word2vec subcommands. The repo had an Arduino sketch (sketch_jul9a/sketch_jul9a.ino) that reads a microphone on A0 and outputs amplitude values over serial at 9600 baud.

Goal

Add a cargo run -- uno status command that reads the Arduino’s serial output and displays it in a live TUI.

Changes made

1. Cargo.toml — added serialport = "4.7" dependency for serial port access.

2. src/uno.rs (new, 232 lines) — two subcommands:

uno listen — raw serial dump to stdout. Tested and working: reads amplitude values (44–65 range from the mic) at 9600 baud from /dev/ttyUSB0.
uno status — TUI with:
- Header bar showing port/baud
- Live amplitude display (turns green bold when >30 threshold)
- Rolling line chart (200 samples, auto-scaling Y axis)
- Stats bar: min, max, avg, sample count
- Quit with q or Esc

3. src/main.rs — wired in the module, match arm, and updated help text.

Issues encountered and resolved

Issue	Cause	Fix
Rust toolchain not installed	Fresh dev machine	Installed via rustup
`libudev-dev` missing	`serialport` crate needs it	`apt install libudev-dev`
Permission denied on `/dev/ttyUSB0`	User not in `dialout` group	Use `sg dialout` (same pattern user already used)
ENXIO error running through `sg`	`sg` detaches stdin from the TTY, so `enable_raw_mode()` fails	Rewrote the read loop to use `BufReader` (same pattern as `listen`); added a helpful error message directing the user to `sudo usermod -a -G dialout`

How to use

# Recommended: add user to dialout group once, then run directly
sudo usermod -a -G dialout $USER
# log out & back in

cargo run -- uno status          # TUI with chart
cargo run -- uno listen          # raw serial dump

Git

b2b62f8  feat: add uno subcommand for Arduino serial monitor
  5 files changed, 433 insertions(+), 12 deletions(-)
  create mode 100644 src/uno.rs

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