Shelly Plus Add-on wiring diagram

Every job, terminal by terminal

1. Wire a soil moisture sensor

   Wire a soil moisture sensor

   An analogue soil moisture sensor takes three wires, shown here in the Truebner SMT50's colours. Brown, the sensor's supply, goes to VCC on the 1-Wire side. White goes to GND, and yellow, the moisture output, to ANALOG IN on the other side. The green wire is the SMT50's temperature output: leave it unconnected unless you want to read temperature instead. Only the three terminals in use are drawn; the Add-on has more on both sides.

   Terminals for wire a soil moisture sensor on the Shelly Plus Add-on

   Terminal	What it does here
   VCC	Sensor power, 3.3 V: brown on the SMT50
   GND	Ground: white on the SMT50
   ANALOG IN	Moisture output, 0 to 10 V: yellow on the SMT50

   Not used for this sensor, so not drawn: the other VCC, DATA and GND terminals on the 1-Wire side, and DIGITAL IN, VREF OUT and VREF+R1 OUT on the analogue side.

   Supply: 3.3 V from the Shelly

   See the soil moisture watering guide

2. Wire a DS18B20 temperature probe

   Wire a DS18B20 temperature probe

   A DS18B20 probe has three wires, all on the Add-on's 1-Wire side. Red, the probe's supply, goes to VCC, yellow, the data line, to DATA, and black to GND. The 1-Wire side has three sets of VCC, DATA and GND, joined on the board, so any set works, and up to five probes can share them. Only the three terminals in use are drawn.

   Terminals for wire a ds18b20 temperature probe on the Shelly Plus Add-on

   Terminal	What it does here
   VCC	Probe power, 3.3 V: red
   DATA	1-Wire data: yellow
   GND	Ground: black

   Not used for one probe, so not drawn: the other two sets of VCC, DATA and GND on the 1-Wire side, and everything on the analogue side.

   Supply: 3.3 V from the Shelly

   See the roof-space fan guide