DavisSi1000 - Firmware for SiLabs Si1000 ISM radios for Davis ISS weather protocol

This firmware is based upon the SiK telemetry radio firmware from http://github.com/tridge/SiK

It implements the receiving side of the Davis ISS 900MHz wireless weather protocol. This will allow a 3DR telemetry radio to be used as a USB enabled Davis weather console.

For more explanation see this discussion:

http://www.wxforum.net/index.php?topic=18718.0

How To use

First you need a 3DR 900MHz radio, either a TTL serial or USB version:

http://store.diydrones.com/3DR_Radio_USB_915_Mhz_Ground_module_p/br-3drusb915.htm http://store.diydrones.com/3DR_Radio_915_Mhz_Air_module_p/br-3dr915.htm

plus an antenna: http://store.diydrones.com/ProductDetails.asp?ProductCode=WI-W1063-900mhz-2dbi

For really long range reception, get a RFD900 instead:

http://rfdesign.com.au/index.php/rfd900

Then you need to load the DavisSi1000 firmware. You can build the firmware yourself on Linux using sdcc and make, or you can download a prebuilt firmware here:

http://uav.tridgell.net/DavisSi1000/firmware

For the 3DR radio you will need the radiohm_trp.ihx file. For the RFD900 you will need radiorfd900a.ihx.

To upload your firmware use the Firmware/tools/uploader.py python script.

Connecting and Protocol

After the firmware is installed you can connect to the radio at a baudrate of 57600. It will initially display a series of messages like this:

Searching 3 at 907868377 Hz Searching 4 at 922418792 Hz Searching 5 at 905359466 Hz

that shows the time since reset in seconds, and the frequency it is looking on.

Once it finds your ISS it will display messages like this once every 2.7 seconds:

{ "transmitter_id": 2, "RSSI": 128, "recv_packets": 22, "wind_speed_mph": 0, "wind_direction_degrees": 215, "temperature_F": 67.95, "humidity_pct": 63.6, "light": 1536, "rain_spoons": 12, "raw": "82 00 98 2A 29 00 E1 45 FF FF ", "version": "1.0" }

These are in JSON format.