pico-enviro-sensor/README.md

Pico Environment Sensor

This firmware, written in Rust using embassy-rs, is designed for the Raspberry Pi Pico 2 W platform using the RP2350 microcontroller. Its application is an environment-sensing device which can measure CO₂ concentration in the atmosphere, ambient temperature and humidity.

The effects of increased CO₂ concentration on cognitive function become increasingly pronounced at CO₂ concentrations exceeding 1000 ppm. There's a fantastic YouTube video by Kurtis Baute and Tom Scott which you can watch for a short summary. Open your window right now!

Building

Prerequisites

• Rust compiler & cargo package manager: https://www.rust-lang.org/
• RPi Pico SDK: https://github.com/raspberrypi/pico-sdk
• RPi picotool: https://github.com/raspberrypi/picotool
• ARM bare metal compiler toolchain
  • arm-none-eabi-gcc (& arm-none-eabi-newlib) on Arch Linux, your system may have different package names
• The ARMv8 or RISC-V Rust toolchain:
  • ARMv8: rustup target add thumbv8m.main-none-eabihf
  • RISC-V: rustup target add riscv32imac-unknown-none-elf

Environment configuration

This build system assumes the environment variables: PICO_BOARD, PICO_PLATFORM & PICO_SDK_PATH are set. picotool should also be available in the PATH.

The env-vars.sh script sets these values to pico2_w, rp2350-arm-s and my personal Pico SDK path, respectively. The environment variable definitions in this file can be set with source ./scripts/env-vars.sh.

Compiling & running

• cargo build (or cargo build --release)

If you wish to run the binary on your Pico (connected in BOOTSEL mode):

• cargo run (or cargo run --release)

TODO / Future improvements

• Companion smartphone app using BLE to receive measurement data from the device for notifications & further analysis/tracking
• Low-power state, reducing screen brightness, sensor sampling rate and putting periphals to sleep
• 3D printed case housing the MCU, sensor, display and rechargable lithium ion battery