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Shelly Plus Add-on

Device identification

  • Device name: Shelly Plus Add-on

Short description

Shelly Plus Add-on (the Device) is a galvanically isolated sensor interface to the Shelly Plus and Gen3 devices.

Main applications

  • Residential

  • MDU (Multi Dwelling Units - apartments, condominiums, hotels, etc.)

  • Light commercial (small office buildings, small retail/restaurant/gas station, etc.)

  • Agricultural (greenhouses, hotbed, nurseries, ranches, etc. )

  • Government/municipal

  • University/college

Future integrations

  • Google

  • Amazon

  • Samsung SmartThings

Device electrical interfaces


  • 1 analog input: ANALOG IN

  • 1 digital input: DIGITAL IN


  • 1 reference voltage output: VREF OUT

  • 1 reference voltage through a pull-up resistor output: VREF + R1 OUT

  • 2 ground terminals: GND*

1-Wire interface

  • 3 sensor power supply outputs (connected to the same PCB track): VCC

  • 3 sensor data terminals (connected to the same PCB track): DATA

  • 3 ground terminals: GND*

  • Connected to the same PCB ground layer.

Add-on interface

  • Shelly proprietary serial interface to connect to a Shelly Plus device

Supported sensors

  • Up to 5 DS18B20

  • Single DHT22

  • NTC resistors with 10 kΩ nominal resistance and β=4000 K

  • Photoresistors

  • PIR sensors

  • Soil moisture sensors

  • Ultrasonic proximity sensors

  • Capacitive liquid level sensors

  • Sound detectors

  • Other analog sensors with 0 to 10 V output voltage





Size (HxWxD):

37x42x15 ±0.5 mm / 1.46 x 1.65 x 0.59 ±0.02 in


105 g / 3.70 oz

Shell material:


Screw terminals max torque:

0.1 Nm / 0.89 lbIn

Conductor cross section:

max. 1 mm² / 17 AWG

Conductor stripped length:

4.5 mm / 0.18 in




Ambient temperature:

-20 °C to 40 °C / -5 °F to 105 °F


30 % to 70 % RH

Max. altitude

2000 m / 6562 ft


Power supply voltage AC:


Power supply voltage DC:

3.3 V (from Shelly plus device)

Power consumption:

< 0.5 W (without sensors)

Output circuits ratings

VCC max. current:

10 mA

VREF OUT max. current:

1 mA

VREF+R1 OUT resistor

10 kΩ

Shelly Plus device firmware capabilities

Shelly Plus Addon supporting devices:

Shelly Plus devices:

  • Shelly Plus 1/1PM

  • Shelly Plus 2PM

  • Shelly Plus i4/i4DC

  • Shelly Plus 0-10V Dimmer PM

  • Shelly Plus RGBW PM

Shelly Gen3 devices:

  • Shelly 1/1PM Gen3

  • Shelly i4/i4DC Gen3

  • Shelly Dimmer 0/1-10V PM Gen3

Temperature reading:

Depends on the DS18B20 or DHT22 sensors

Humidity reading:

Depends on the DHT22 sensor

Digital input:

-15 V to 0.5 V (True) / 2.5 V to 15 V (False)*

Analog input range:

0 to 100%

Analog input report threshold:


Voltmeter range:

0 to 10 V

Voltmeter report threshold:

0.1 V**

Analog input / Voltmeter accuracy

Better than ±5%

* Logic can be inverted in the digital input settings
** Can be configured in the analog input / voltmeter settings

Basic wiring diagrams

Shelly Plus Add-on 1-Wire wiring diagrams

Shelly Plus Add-on analog input wiring diagrams



Components and APIs

Printed user guide

Shelly Plus Add-on multilingual printed user and safety guide.pdf


Shelly Plus Add-On multilingual EU declaration of conformity.pdf

Installation guides

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