NOTE: This firmware works with the all variants of RS41 radiosondes, with the new RSM414 too, bringing full hardware and software support for everyone. More below.
Vaisala some time ago began launching new RS41 sondes, with new internal design. They can be recognized by a last digit of 4 of the PCB model (eg. RSM414, RSM424). This firmware is an approach for reusing them as amateur devices for many different purposes. It also brings support for older models.
- Radiosondes?
- RS41-NFW Firmware features
- Installation guide
- Firmware flashing
- Firmware compilation
- Firmware and device operation
- RSM414 hardware
- Firmware changelog
- Authors and contributors to this branch
- References
- Final notes
These small electronic devices are used by weather instututes to perform atmospheric sounding and high altitude measurements, up to the stratosphere (HAB - high altitude balooning). After the flight, usually they are meaningless for the launch company, so they can be collected by people (verify this according to the certain launch site). This acvitivty is called radiosonde hunting
The most simple and costless way of collecting radiosondes is to track them on sites like radiosondy.info or SondeHub (previously HabHub).
Another, more advanced way is to hunt them with radio receivers. Most of them transmit on the EU 400-406 MHz radiosonde band, near an amateur 70cm band. You can do that by a simple direction finding with a directional (for example Yagi) antenna and a handheld receiver.
But, currently the best way is to utilize a Software-Defined Radio (SDR, for example an RTL-SDR v3 / v4, Nooelec SDR, RSP1 or HackRF) together with a 70cm band antenna (dipole should work for sondes in air as far as 100km, the best is a high gain Yagi, with this setup you could easily hear a radiosonde hundreds kilometers away) and a specialized software for a computer, laptop or a Raspberry Pi. On the internet you will find lots of tutorials for receiver setup, tracking and hunting of them.
Kind note: After each hunt, either successful or not, please change the radiosonde status on the previously mentioned trakcing sites. This will not only let many people save on fuel and patience, but also allow everyone to take a look on sounding statistics and other things. On the most simple site for tracking (SondeHub) you don't even need to create an account to change the sonde status, which only takes a minute.
It's an unpleasant feeling, when after driving dozens of kilometers in search for radiosonde you come across an empty field without any ballon traces.
For more details about HAB and sonde hunting, please look on google and social media, there is a ton of valuable content.
- Full support for ALL RS41 versions (eg.
RSM421,RSM414,RSM424), including the new ones with the '4' at the end of the PCB model. - Multiple, customizable transmission modes
- Horus Binary 4FSK v2
- One of the most efficient radio modes for HAB and other simple telemetry designs, allows for decoding of very weak signals
- APRS
- 1200 baud, with 1200Hz and 2200Hz tones achieved by FSK switching in a loop
- Standard balloon and WX reporting format
- RTTY
- Customizable 45 and 75 baud rates, possibly other available
- Customizable tone spacing as a multiplication of 270Hz (minimum Si4032 offset)
- Compliant with UKHAS format
- Morse code (CW)
- Customizable wpm speed and dot length
- Compliant with UKHAS format
- PIP
- Beacon operation, transmitting short beep with a specified interval, which could be used as a foxhunting TX device
- Horus Binary 4FSK v2
- Thorough support of RS41 hardware, including GPS, radio, power circuitry, reference heating etc. ...and:
- Support for onboard boom sensors, including temperature and humidity sensors
- Detailed in-built debugging features via LED status and serial messages
- Onboard button allowing user to change different operation modes and parameters 'in-flight'
- Safety features, including GPS watchdog and position improvement (these two improve flights in environments with interference/noise), battery voltage and temperature protection, sensors defrosting
- Support for extending hardware capabilities, including external I2C or UART sensors - including OIF411
- Power saving features, including GPS power management (together with powersaving modes and complete disable for stationary use cases) and automatic radio adjusting
- User-friendly firmware and IDE allows users to easily customimze the device operation
- Weather station mode, supporting APRS WX reporting
- Flight controling algorithms. Ability to rapidly send packets when below set altitude.
- Calibration modes for temperature and humidity sensor on the silver boom
- And many more - mentioned in changelog and manual
A thorough, detailed project guide is available at the links below.
If you want to fully utilize all capabilities of this firmware, please, read the documentation in the following header order:
See: fw/FLASHING.md
See: fw/COMPILE.md
See: fw/OPERATION_MANUAL.md The options in the firmware file should be self explanatory (alongside with the comments near them). This manual should be up-to-date, but there may be some issues with it (it's hard to manage that long markdown file, sorry :) ). If you have any problems, questions and suggestions, feel free to open issues here!
See: hw/README.md
v38- bugfix for delay variable initialization, which could lead to overflow if set at 65 seconds or higherv37- fox hunting mode, which can transmit a melody over NFM, CW pip, CW morse with additional message contents of location below voltage warning and battery voltage reporting, this mode operates in as low power consumption as possible (measurement circuits disabled, heaters disabled, GPS disabled, radio sleeping between transmissions). The gpsSpeed value in Horus v2 payload is now reported in km/h (instead of m/s as before). Small changes in startup and calibration procedure.v36- changes in button operation algorithm - user can select between completely disabled button functions, sonde shutdown on button press or extended mode, which allows to change some parameters of the sonde. The button operation is available now throughout the whole operation of the sonde, in some limited areas (like calibrartion) the button can shutdown the sonde now.v35- fixed boom calibration issue, which could lead to worse humidity compensation. Enhanced defrosting algorithm, that doesn't impact the readings.v34- support for onboard humidity sensor reading (not the most accurate method, but gives reasonable readings with easy use). Humidity module calibration modes and auto-compensation (some parts of it known as zero-humidity check). Defrosting features. Reference resistors warming to maintain their temperature. Automatic temperature compensation for humidity module sensor readings. Depreciated oscillator heating capabilities - RTTY isn't widely used, especiallu at 75-baud and the option was very power hungry - now the resistors are used like from factory, to slightly warm up the reference resistors and capacitor.v33- added option to disable the button operation. New dataRecorder feature, that saves most important statistics from flight and transmits them in APRS comments once for a specified time (by default every 10 minutes). Flight computing abilities, that measure flight parameters (min/max values; flight, burst and landing phase detection, etc.). New ultraPowerSaveAfterLanding feature, that lowers the power consumption as much as possible 30 minutes after landing (GPS is fully OFF, sensors and peripherals get disabled) and transmits the last coordinates every 10 minutes via Horus and APRS (+ dataRecorder statistics). Added a watchdog that resets the CPU after specified time (2 weeks by default) to protect from overflowing.v32- added APRS 2 reporting modes - normal HAB tracking format and WX report format for weather station use. GPS operation modes - disabled, max performance, power saving; utilizing automatic powersaving switching to ensure best power consumption with reliable tracking. New feature, which transmits Horus packets as fast as possible (6s) at low altitudes (< 1km) for specified time when descending, to ensure that the lowest frame is captured. RTTY and Morse TX format now compliant with UKHAS formatting.v31- added APRS support (not copied), GPS no-fix timeout watchdog (resets the chip if it can't get a fix for long enough), GPS performance improvement in position gathering, 2nd Horus TX frequency (with alternating mode and repeating packest), code clean-up, other small fixes and preparations for next releasesv30- added vertical velocity calculation and reporting via Horus v2. New and more accurate synchronization of delays between TX modes, fixnig issue were the delay was doubled in certain conditions.v29- final fix for GPS dynamic model setting - both old and new boards tested (new tested in-flight, old checked through u-center and will be tested in-flight soon). GPS tracking should be now trustworthy (still no verification mechanism, but shouldn't be for now a big concern).v28- full compatibility of default Horus v2 payload format with RS41ng default format. Detection of external power supply (for example via programmer) disabling button functionality to prevent unpredictable device operation.v27- support for sensor boom - accurate readings of external temperature and humidity module temperature (humidity measurement not supported yet), Horus v2 format corrections (default payload uses the same format as RS41ng).v26- added missing feature on older RS41 (RSM4x1,RSM4x2) sondes - reference heating, which is activated by Si4032 GPIO pin.v25- powerSave mode, featuring automaticaly-adjustable TX power and transmission intervals, based on the altitude. Changed default values of the firmware.v24- some improvements in the GPS Dynamic Model setting, support for both old and new sondes, simple VALSET & VALGET validation mechanism for the new sondes. The Airborne 1G mode is still experimental!v231- fix issues of the previous release v2.3, thanks to (still) this issue #3. Changed OIF411 data interpretation according to the operation manual (raw data division).v23- added experimental uBlox GPS Airborne 1G Dynamic Model selection via UART of the module, thanks to this issue #3v22- support for OIF411 ozone sounding system (including decoding the ozone info and transmision to ground), XDATA port mode selection (disabled, debug UART, XDATA UART), easy method of changing the payload-ID in Horus v2 mode, height activated oscillator heaterv21- added support for old RS41 models (RSM412)v20- initial public release, releases before this were never published
Incoming features:
- Somehow get the RPM411 to work
- Authors
- Franek 'nevvman' (no callsign, yet)
- Contributors - speical thanks to:
- My dad, for his help in catching the radiosondes and suggestions
- videobuff - helped with lots of issues
- darksidelemm - for help with GPS settings, Horus and sensors
- zanco PE2BZ - for a test flight and other notes
- Ludwik SP6MPL - for a few flights and big help in development
- Mateusz SP3WRO - for test flights, kind words and help in development, and also his team
- radioszynka blog team - for article about this project
- PC9DB - TX formats etc.
- KB8RCO - big thread about APRS, WX use and others
- whallman DF7PN - much help in discussions
- Damian SQ2DEF and his team - SQ6KXY, Paweł, Lechu, McXander, wprzyb, Michał, Hubert...
- obi7zik
- People from Radiosondy Polska group - Jarosław, Wojtek... - kind words in a local group argument
- RS41ng - inspiration for this project (NFW is not a fork of any kind (too much differing to be called so), just a few pieces of it's code structure is used here)
- RS41ng - issues discussion about new models and supporting them
- RS41HUP - also inspiration
- radiosonde_hardware - made reversing the new version easier
- Horus Binary - awesome HAB radio protocol
- Arduino APRS library, partially utilized here to create APRS messages
The creator of this project isn't at all responsible for any kind of harm made by devices operated with these instructions. Follow your local law about radio transmissions and ballon flights. This device isn't a certified airplane. Altough the firmware tested successfully on a dozen of flights, it still is a 'hobbyst' project. Have a nice day!