Probes and sensors

DS18B20 temperature probes

Waterproof DS18B20 probes communicate over 1-Wire: several probes share a single pin.

• Wiring: red to 3.3 V, black to GND, yellow (data) to the chosen pin, with a 4.7 kΩ resistor between data and 3.3 V (only one per bus).
• Identification: in the sensor form, the search button lists the addresses of the probes on the bus. Choose each probe’s address so you don’t mix them up.
• Interval: 30 seconds by default, adjustable.
• Silent probe: unplugged, or missing when the controller starts, it shows “No reading” after 3 intervals without a reading, rather than keeping its last temperature.

These probes can be used as a threshold condition in rules.

Float switches

A float switch is an on/off sensor. Wire it between the pin and GND: the input is configured with the ESP32’s internal pull-up resistor. Debouncing prevents false triggers caused by ripples.

• GPIO 34 to 39: input-only, without internal pull-up. Add a 10 kΩ resistor between the pin and 3.3 V, otherwise the input “floats” and the level changes at random.
• Pin of an expansion module (PCF8574): supported, the module provides the pull-up.

Float switches are used as a state condition in rules: ATO, high-level safety, sump.

Analog inputs

Other sensors connect to an ESP32 analog input (ADC), read every minute. On the ESP32, prefer the ADC1 pins (GPIO32 to 39), as ADC2 is unavailable while Wi-Fi is active.

History

Each sensor’s values are kept (365 days by default, adjustable with AQUAS_SENSOR_READING_RETENTION_DAYS) and can be viewed as a chart from the Sensors (Capteurs) tab.