- high precision outdoor temperature 0.1 max deviation
- high precision outdoor relative humidity 1.5% max deviation
- high precision barometric pressure max 0.5 hPa deviation
- outdoor unit is wireless 868 mhz (EU) with CRC (possibly encryption)
- possible to add more sensors later (i2c is possibly the easiest option)
- send data to database / MQTT etc.
- SHT-35D Temperature / Humidity sensor by Sensirion with IP67 cap (for outdoor)
- SHT-31D Temperature / Humidity sensor by Sensirion (for indoor)
- BMP388 Temperature / Barometric pressure sensor by Bosch
- Atmel 328P chip (or complete Arduino)
- Prototyping boards
- 2x RFM69HCW Transceiver Radio (+ SMA connectors and antenna, or just use a wire)
- Soldering skills incl. soldering iron, tin, sponge
- Arduino IDE and a way to program the 328P (directly on arduino, ZIF TX/RX, FTDI etc.)
- Different color wiring 22 AWG minimum
- Davis radiation shield 7714 or equivalent https://www.davisinstruments.com/product/radiation-shield/
- 5v power supply, for example a Mean Well 1297280
- Silicone (for outdoor use)
- outdoor housing, minimal IP65 rated and water proof wire pass-troughs
- Flux cleaner spray
- PCB protection spray (do not spray the sensors or the connection pins!)
- Arduino MKR equivalent with Wifi (MKR 1010 for example)
- Arduino IDE
- Libraries:
- https://github.com/adafruit/Adafruit_SHT31
- https://github.com/adafruit/Adafruit_BMP3XX
- https://github.com/PaulStoffregen/RadioHead
You can get the sensors from multiple vendors, some already use breakout boards which will make the build easier. Make sure the outdoor sensors are covered so they dont get wet. Always use i2c.