Add Cotech 36-7959 samples (#343)

tests/cotech/cotech_36-7959/01/README.md

@@ -0,0 +1,18 @@
+
+# Cotech 36-7959 weatherstation
+
+## Measured values
+
+File,Temp (celcius),Humidity,Gust,Wind,Direction,Rain,Dew point,Feels like
+g001_433.92M_1000k.cu8,"22,8",34,"0,0","0,0",S,"0,9","6,2","22,8"
+g002_433.92M_1000k.cu8,"22,8",34,"0,0","0,0",S,"0,9","6,2","22,8"
+g005_433.92M_1000k.cu8,"22,8",34,"0,0","0,0",N,"0,9","6,2","22,8"
+g007_433.92M_1000k.cu8,"22,8",34,"0,0","0,0",W,"0,9","6,2","22,8"
+g009_433.92M_1000k.cu8,"22,8",34,"0,0","0,0",E,"0,9","6,2","22,8"
+g013_433.92M_1000k.cu8,"22,8",34,"2,0","0,6",S,"0,9","6,2","22,8"
+g015_433.92M_1000k.cu8,"22,8",34,"1,7","1,1",S,"0,9","6,2","22,8"
+g020_433.92M_1000k.cu8,"22,9",34,"0,0","0,0",SW,0,"6,2","22,9"
+g022_433.92M_1000k.cu8,"22,9",34,"0,0","0,0",NW,0,"6,2","22,9"
+g024_433.92M_1000k.cu8,"22,9",34,"0,0","0,0",NE,0,"6,2","22,9"
+g026_433.92M_1000k.cu8,"22,9",34,"0,0","0,0",SE,0,"6,2","22,9"
+g029_433.92M_1000k.cu8,"22,9",34,"0,7","0,1",S,"4,8","6,2","22,9"

tests/cotech/cotech_36-7959/01/samplerate

@@ -0,0 +1 @@
+1000000

tests/cotech/cotech_36-7959/README.md

@@ -0,0 +1,33 @@
+# Cotech 36-7959 weatherstation
+
+Believe the weatherstation is a branded version of [UNIT CONNECTION TECHNOLOGY's model _FT020](http://www.uctechnologyltd.com/prod_view.aspx?TypeId=29&Id=265&FId=t3:29:3).
+
+Flexcoder
+```
+rtl_433 -X n=cotech-36-7959,m=OOK_MC_ZEROBIT,s=488,r=1200,preamble={12}014
+```
+
+Running _reveng_ to reverse engineer the CRC calculation
+```
+reveng -w 8 -s [samples from flexcoder]
+ Result: width=8  poly=0x31  init=0xc0  refin=false  refout=false  xorout=0x00  check=0x0d  residue=0x00  name=(none)
+```
+
+## Data mappings
+
+- 4 bits = Never changes
+- 8 bits = Changes when replacing batteries or when resetting device, probably an id
+- **1 bit**  = 0 = Ok battery, 1 = Low battery
+- **1 bit**  = Wind direction is defined by a byte later on in the sequence. When degrees are over 255 (byte max value) this value is set to 1 and the wind direction starts from 1 again. So when this is = 1 it basically means "wind direction value + 255"
+- **1 bit**  = Wind and gust are also defined by a byte later on in the sequence. Specification states it can show wind strength up to 50m/s. Guessing this bit works same as previous bit for wind direction i.e. if this is set to 1 wind (or gust) is equal to (wind value + 255) / 10
+- **1 bit**  = same as above. Don't know which is which... need to bring out the compressor and manually create some strong wind.
+- **8 bits** = Wind, decimal value / 10 to get m/s
+- **8 bits** = Gust, decimal value / 10 to get m/s
+- **8 bits** = Wind direction, decimal value for degrees
+- **4 bits** = Always the same, 4 zeros, no clue... might belong to the following rain value
+- **_12 bits_** = Rain value / 10 => mm. Don't know if this is actually 12 bits, if it cycles or how it works. So far I have only seen this value increasing (exept for when device was reset). Might also contain the previous 4 bits
+- 4 bits = Always the same, 1000, no clue
+- **12 bits** = Temperature. This value is given in fahrenheit with the formula: (value - 400) / 10
+- **8 bits** = Humidity, decimal value giving the percentage
+- 24 bits = Always the same, crc-padding?
+- **8 bits** = CRC8 Checksum (width=8  poly=0x31  init=0xc0  refin=false  refout=false  xorout=0x00  check=0x0d  residue=0x00)