Uses a D1 Mini and Arduino code with an HTU21D for ambient sensing and two DS18B20 OneWire sensors for inlet and outlet temperature measurement. The derivative of the temperature difference across the heat pump detects the heat pump mode.
ADS1115+ESP-01 (1M) OTA updated based on https://goo.gl/AH8Y3w sketch adapted to my 30A CT and 6V transformer. ESP is powered from a separate 3.3V source.
This is a weather station, to monitor the soil and Atmospheric temperature, relative humidity, and soil moisture levels during the day and night