Build and program temperature, pressure and humidity sensor (bme280)

[cletomartin]

• [x] Build the sensor and attach it to the RPI
• [x] Program the sensor
  • [x] Build a function get_tph() to collect temperature, pressure and humidity that returns a dictionary like {"timestamp": ts, "temperature": temp, "pressure": prs, "humidity": hum}.
  • [x] Document the process