rs41_rust

This repo contains a new approach to a firmware for the Vaisala RS41 radiosonde, written entirely in Rust.

⚠️ 2024-05-03: Today I captured a RS41 with a new microcontroller: STM32L412. This repo is developed on the old revision (with STM32F100). I will create a branch for the new one asap. Do not attempt to flash a new revision!

Obtaining the sonde

The web contains lots of information about how to get and program a RS41. I am using a standard NXP LPC Link 2 with CMSIS-DAP firmware works with an adapter.

Please unsolder and remove the antenna before first programming!

I have additionally mounted a SMA plug to connect to a SDR (LimeSDR) or analyzer, with a 10 dB pad between.

Sonde hardware

bazjo did an amazing job in reverse-engineering the RS41's PCB. Please read his documentation: https://github.com/bazjo/radiosonde_hardware/tree/master/Vaisala_RS41

Goals, requirements

For a planned HAB launch the sonde has following requirements:

• Transmit location (coordinates and altitude)
• Modulation: GFSK and Hellschreiber mode
• Reading environmental (temperature, pressure) sensor optional
• Additional UART port at external connector

Already working:

• Flashing the sonde
• RTIC runs
• LEDs blinking
• Power button (reading ADC)
• Radio configuration:
  • frequency
  • tx power
  • modulation
  • ...
• Transmitting data via GFSK
• Hellschreiber mode (needs fine tuning)
• Generating ubx messages
• Sending ubx messages to u-blox GPS receiver
• Parsing ubx messages from u-blox

Next steps:

• Improving GFSK receiver (GNU Radio)

Unlocking the flash

First terminal: open openocd

openocd -f interface/cmsis-dap.cfg -c "transport select swd"  -f target/stm32f1x.cfg

Second terminal: commands to openocd and unlock

telnet 127.0.0.1 4444

> flash protect 0 0 15 off

Building

$ git clone https://github.com/arnobert/rs41_rust
$ git clone https://github.com/arnobert/si4032_driver-rs
$ cd rs41_rust
$ cargo build

With Hellschreiber mode:

$ cargo build --features "hell"

Flashing the sonde, GFSK/HELL:

$ cargo embed
$ cargo embed --features "hell"

Cargo embed auto-detects the LPC Link.