Shelly Pro Sensor Add-on – DIN Rail Sensor Module

Product detailed description

🌡️ Turn your Shelly Pro into a professional measuring hub

The Shelly Pro Sensor Add-on is a DIN rail sensor expansion module that gives Shelly Pro devices the one thing they lack on their own – the ability to read real values from their surroundings. Instead of a single switching output, your enclosure now also reports temperature, humidity, level, light or the state of a motion detector, all inside the same app and the same scenes you already use.

The module is galvanically isolated, so the sensor side is electrically separated from the mains side – which, with long cable runs to sensors outside the enclosure (a well, a warehouse, a greenhouse), is the difference between a reliable installation and endless interference troubleshooting. It draws 12 V straight from the connected Shelly Pro device and consumes less than 0.5 W with no sensors attached.

Four input types in a single 19 mm wide module

The terminal block gives you 2× 1-Wire data channels (independent, each taking up to five DS18B20 sensors or combined temperature/humidity DHT22 sensors), 2× analogue inputs 0 – 10 V accurate to better than ±5 %, 2× digital inputs ±15 V with optional logic inversion, and 1× potential-free solid-state output (max. 30 V / 300 mA). You also get a VREF reference voltage, a VREF + R1 branch with a 10 kΩ resistor for resistive sensors, and a VCC supply.

DS18B20 temperature sensors wire straight into the terminals – we stock them with a 1 m cable for measuring inside the enclosure and with a 3 m cable when you need to measure in a tank, on a pipe or in the next room. Since each channel takes up to five sensors, a single module can cover an entire buffer tank from top to bottom.

In practice one sensor add-on handles a thermometer in a tank, a soil moisture probe in a greenhouse, an ultrasonic level meter in a well and a door contact all at once – and still switches something itself on top of that. Thanks to the VREF + R1 input you can also connect ordinary NTC thermistors (10 kΩ, β = 4000 K), photoresistors and capacitive level sensors, in other words sensors with no electronics of their own. You will find the sensors themselves in the Smart Home Sensors category.

The module is not a standalone device – it always works as an add-on to a host Shelly Pro running firmware 2.0 or later. That is also its biggest advantage: it needs no IP address of its own, no power supply and no extra slot on your network, because everything runs through the device already sitting in your enclosure. The full range is in our Shelly product offer.

Who the Shelly Pro Sensor Add-on is for

• Heating and heat pump installers who need temperatures from several points of a buffer tank brought into the enclosure at once.
• Owners of greenhouses, gardens and irrigation systems – soil moisture, temperature and light as the trigger for automatic watering.
• Warehouse and production facility managers who have to document temperature and humidity over time and react when a limit is exceeded.
• Home Assistant users and advanced installations that want local data with no cloud and no extra gateway.
• Anyone who already has a Shelly Pro in the enclosure and wants more out of it than just switching.

🔧 Use cases

• Measuring temperature in a buffer tank or boiler – up to 5 DS18B20 sensors on one channel, temperature top and bottom, and pump switching based on the difference.
• Monitoring temperature and humidity in a warehouse or server room – DHT22 plus a notification when the set threshold is crossed.
• Automatic irrigation based on soil moisture – a capacitive probe on the 0 – 10 V analogue input starts the pump only when it actually makes sense.
• Monitoring the level in a well or rainwater tank – an ultrasonic or capacitive level sensor with dry-run pump protection.
• Checking the state of doors, windows or service hatches via a potential-free contact on the digital input.
• Controlling lighting by daylight level – a photoresistor on the VREF + R1 input.
• Motion detection in technical rooms – a PIR sensor wired straight into the enclosure, with no extra battery-powered device.

Key features and protocols

Why choose the Shelly Pro Sensor Add-on

• Four input types at once – 1-Wire, 0 – 10 V analogue, ±15 V digital and a potential-free contact in a single 19 mm wide module.
• Galvanic isolation – the sensor side is separated from the mains side, which means less interference on long cable runs to sensors.
• Takes neither power nor a slot on your network – it draws 12 V straight from the host Shelly Pro.
• Works locally – sensor data is processed inside the device itself, with no dependence on the cloud.

Compared with the Shelly Pro LoRa Add-on, this module solves a completely different problem: the LoRa Add-on extends the range of a link between two enclosures, while the Sensor Add-on extends what a single device can do by adding measurement. In more complex installations they complement each other – you collect sensor readings through the Sensor Add-on and send the values to a remote location over LoRa. If you need to switch rather than measure, take a look at the Shelly Pro 3EM Switch Add-On.

Frequently asked questions

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