Project 7: Embedded LED Controller (No OS, No Problem)

An LED light controller running on a microcontroller (like Raspberry Pi Pico) with no operating system—pure bare-metal Rust that directly manipulates hardware registers.

Quick Reference

Attribute Value
Primary Language Rust
Alternative Languages C (traditional choice for embedded)
Difficulty Level 3: Advanced
Time Estimate 2-3 weeks
Knowledge Area Embedded Systems / No-std Rust / Hardware
Tooling Raspberry Pi Pico, Embassy or RTIC framework
Prerequisites Projects 1-2 completed, some electronics knowledge helpful

What You Will Build

An LED light controller running on a microcontroller (like Raspberry Pi Pico) with no operating system—pure bare-metal Rust that directly manipulates hardware registers.

Why It Matters

This project builds core skills that appear repeatedly in real-world systems and tooling.

Core Challenges

  • Writing no_std code without the standard library → maps to core vs std library
  • Directly accessing hardware registers safely → maps to volatile reads/writes
  • Managing resources without a heap → maps to static allocation
  • Interrupt handling in Rust → maps to RTIC or Embassy frameworks

Key Concepts

  • No-std Rust: “The Embedded Rust Book” - rust-embedded.github.io
  • Memory-mapped I/O: “Making Embedded Systems, 2nd Edition” Chapter 4 - Elecia White
  • Volatile access: “Programming Rust, 2nd Edition” Chapter 22 - Jim Blandy
  • Embedded HALs: “Rust for Rustaceans” Chapter 12 - Jon Gjengset

Real-World Outcome

Physical setup: Raspberry Pi Pico + 8 LEDs + button

Your Rust code controls:
- LED patterns (chase, fade, rainbow)
- Button input handling via interrupt
- PWM for brightness control
- USB serial for live control from computer

┌─────────────────────────────────────┐
│  🔴 🟢 🔵 🟡 🔴 🟢 🔵 🟡           │
│         ← LEDs                      │
│                                     │
│         [Button]                    │
│                                     │
│  USB → Computer for control         │
└─────────────────────────────────────┘

$ screen /dev/ttyACM0
> pattern chase
LED pattern: chase
> speed 50
Chase speed: 50ms
> brightness 75
Brightness: 75%

Implementation Guide

  1. Reproduce the simplest happy-path scenario.
  2. Build the smallest working version of the core feature.
  3. Add input validation and error handling.
  4. Add instrumentation/logging to confirm behavior.
  5. Refactor into clean modules with tests.

Milestones

  • Milestone 1: Minimal working program that runs end-to-end.
  • Milestone 2: Correct outputs for typical inputs.
  • Milestone 3: Robust handling of edge cases.
  • Milestone 4: Clean structure and documented usage.

Validation Checklist

  • Output matches the real-world outcome example
  • Handles invalid inputs safely
  • Provides clear errors and exit codes
  • Repeatable results across runs

References

  • Main guide: LEARN_RUST_DEEP_DIVE.md
  • “Making Embedded Systems, 2nd Edition” by Elecia White + “The Embedded Rust Book”