Comparison of Shelly Plus Addon with Shelly Plus Uni
The Shelly Plus Addon and the Shelly Plus Uni are both used to integrate external sensors into the Shelly system. A comparison of these solutions is always useful if the inputs of the primary host device are not sufficient for recording the sensor data. The functionality can either be extended directly via the plug-on Plus Addon or realised as a completely independent module using the Shelly Plus Uni.
The Shelly Plus AddOn ist eine Erweiterungsplatine für bestimmte Shelly‑Modelle (z. B. Shelly Plus 1 oder 1PM). Sie ergänzt diese um zusätzliche Eingänge wie analoge Sensoren, Temperatursensoren (DS18B20) oder Schalter. Das AddOn selbst funktioniert nicht eigenständig, sondern erweitert die Funktionen des Hauptgeräts.
The Shelly Plus Uni hingegen ist ein eigenständiges, universelles Modul. Es kann direkt Sensoren oder Schalter einbinden, zwei Ausgänge steuern und arbeitet komplett über WLAN – ohne zusätzliches Basisgerät. Damit eignet es sich für flexible Anwendungen, bei denen keine feste Installation oder Relais nötig ist.
Comparison of technical data
| Shelly Plus Addon | Shelly Plus Uni | |
| Aussehen |  |  |
| Type | Extension module (attachment) | Stand-alone device |
| Requires host device | Yes (compatible: Shelly Plus 1/1PM, Shelly Plus 2PM, Shelly Plus i4/i4DC) | No (works directly in WlLAN) |
| Power supply | About the host device | 5V DC/9-28V DC |
| Digital inputs | 1 (potential-free or with voltage) | 2 |
| Analogue inputs | 1 (0-10V) | 1 (0-10V / 0-30V) |
| Outputs | None of your own (uses host relay) | 2 potential-free outputs (up to 100mA) |
| Sensors | Up to 5x DS18B20 or 1x DHT22 | Up to 5x DS18B20 or 1x DHT22 |
| Connection type | Is plugged into the Shelly Plus relay | Loose cable ends (strands) |
| Special feature | Safest solution for 230V environments | Extremely small, ideal for DIY & low voltage |
| Documentation | Dokumentation Shelly Plus Add On | Dokumentation Shelly Plus Uni |
Integration of a wide variety of sensors
- Shelly temperature sensor
- Soil moisture sensor
- Motion detector
- Rain sensor
- photoresistor
Decision support
Question
Recommendation
Do you already have a Shelly Plus relay on site?
Plus Addon
Explanation: Utilises the power and WLAN of the existing Shelly. Saves an extra power supply unit, space and an additional IP address in the network.
Do you need to switch a 230V load (e.g. radiant heater)?
Plus Addon
Explanation: Only the add-on can safely switch large loads via the host relay. It also offers an electrically isolated sensor interface.
Do you work with 12V DC or 24V AC?
Plus Uni
Explanation: The Uni is designed for low voltage (e.g. bell transformer). It is extremely flexible and fault-tolerant thanks to its wide voltage range of 9-28V DC.
Do you need to record two separate signals (e.g. 2 contacts)?
Plus Uni
Explanation: While the add-on only has one digital input, the Uni has two. Ideal for monitoring two contacts simultaneously with just one device.
Do you have extremely little space (e.g. behind a circuit board)?
Plus Uni
Explanation: Kleiner als eine halbe Kreditkarte und ohne festes Gehäuse. Er passt in kleine Gehäuse, wo ein Shelly mit Addon zu tief wäre.