updated README for release

README.markdown

@@ -10,3 +10,52 @@ 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 radio~hm_trp.ihx file. For the
+RFD900 you will need radio~rfd900a.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.