- Name in shop: Brifit Thermometer Innen/Ausen, Hygrometer Thermometer mit Außensensor, Raumthermometer, Funk Thermometer mit Großem LCD Display, ℃/℉ Schalter, Ideal für Büro, Haus, Zimmer, Weiß
- Name on box: Brifit Humidity and Temperature Monitor
- Model: FT017TH
- Manufacturer: Unit Connection Technology Ltd, Shenzhen
- Dealer: Shenzhen Amier Technology CO Ltd (amirtec.com)
- Frequency (indicated): 433.92MHz
- powered by two 1.5V AAA batteries
Sensor transmits approximately once per minute.
Measurements with cc1101:
- Frequency: 433.945 MHz
- Symbol rate: 2048 Baud
Recorded with gqrx via RTL2832U/R820T (433.893MHz, AM):
After conversion to binary signal:
Signal is manchester-encoded.
Each transmission contains 3 repeats of the same message.
Each message consists of 65 bits:
| bit range | carried information |
|---|---|
| 0-8 | all high bits, probably sync signal |
| 9-17 | same byte in all transmissions, maybe sensor address? |
| 18-32 | unknown |
| 33-44 | temperature |
| 45-56 | humidity |
| 57-64 | unknown |
I recorded a few transmissions (*.wav)
and compared the received data with the values indicated on the display (displayed-values.yml).
The most significant bit is transferred first (big-endian).
Linear regression models estimate:
temperature_celsius = temperature_index / 576.077364 - 40(intercept at-40°C = -40°F)relative_humidity = relative_humidity_index / 51451.432435
The command-line tool & python library wireless-sensor automatically decodes signals of FT017TH wireless thermo/hygrometers.