An introduction to Shelly Wi-Fi smart devices

An introduction to Shelly Wi-Fi devices

What is Shelly Wi-Fi?

Shelly Wi-Fi is a relatively new smart home brand that is now available in Australia and new Zealand. Shelly devices join your Wi-Fi network – there is no need for a dedicated smart home hub. Using the Shelly Cloud app – or free open source software platforms like Home Assistant or OpenHAB – you can create a powerful smart home for a fraction of the price of traditional automation systems.

Shelly make a lot of smart devices – and it is not always obvious exactly what the differences or use cases are… so in this blog, we will take a deep dive into the different Shelly products available so you can make an informed decision and chose the right Shelly device for your application.  As always, please do not hesitate to contact us if you have questions – we are always happy to help.

Shelly Relays

Shelly Relay (On / Off) Modules

Shelly have around 15 relay modules in their range. That’s a lot of different relay modules that essentially do the same thing… turn the power to connected electrical devices on and off! So why so many? There are subtle (and not so subtle) differences between them all – here is a quick guide…

Shelly Relays Gen. 1 / 2 / 3 Power Monitoring Dry Contact Control Channels Motor Support Comments
Shelly 1 Gen. 1 No Yes 1 No Discontinued
Shelly 1L Gen. 1 No No 1 No Discontinued
Shelly 2.5 Gen. 1 Yes No 2 Yes Discontinued
Shelly 1PM Gen. 1 Yes No 1 No
Shelly 1 Plus Gen. 2 No Yes 1 No
Shelly 1 Mini Gen.3 Gen. 3 No Yes 1 No
Shelly 1PM Plus Gen. 2 Yes No 1 No
Shelly 1PM Mini Gen.3 Gen. 3 Yes No 1 No
Shelly 2PM Plus Gen. 2 Yes No 2 Yes
Shelly 1 Pro Gen. 2 No Yes 1 No DIN Rail / Ethernet support
Shelly 2 Pro Gen. 2 No Yes 2 No DIN Rail / Ethernet support
Shelly 3 Pro Gen. 2 No Yes 3 No DIN Rail / Ethernet support
Shelly 1PM Pro Gen. 2 Yes No 1 No DIN Rail / Ethernet support
Shelly 2PM Pro Gen. 2 Yes No 2 Yes DIN Rail / Ethernet support
Shelly 4PM Pro Gen. 2 Yes No 4 No DIN Rail / Ethernet support
Now let’s delve deeper so you can make an informed decision and select the right Shelly Relay Module for your application…

Shelly Gen. 1, Gen. 2 & Gen. 3 Devices

This is the first major difference between the Shelly On/Off modules – and one that is not plainly obvious. Some Shelly modules are built on Gen.1 (generation 1) technology. Others are the newer Shelly Gen. 2 technology. So in short, without the sales jargon… Gen. 2 is the upgraded version of Gen. 1. Virtually all Gen. 1 Shelly devices have now been discontinued.

Gen. 2 Shelly products can usually be identified with the addition of “Plus” or “Pro” on the end of the product name.

So, what are the main differences between Shelly Gen. 1 and Gen. 2 devices? Let’s compare Shelly 1 (Gen. 1) to Shelly 1 Plus (Gen. 2)…

Gen. 1 Gen 2.

Gen. 3 devices now include Shelly’s custom and proprietary ESP-Shelly-C38F Chipset with expanded 8 MB of memory (compared to 4 MB for Gen. 2 devices). This welcome upgrade in processing power and memory means Shelly Gen. 3 devices run faster and smoother.

Shelly Power Monitoring Relays

One of the other main differences in the Shelly relay range is the ability to measure the power consumption of the connected load. Typically, if the Shelly device is coloured red or black – then it supports power monitoring. Blue coloured Shelly relays do not support power monitoring.

So what’s the trade-off?  Why wouldn’t I just purchase the Shelly energy monitoring versions? Well for one, they are slightly more expensive than their non-power monitoring counterparts – so you may as well save some money if the energy monitoring feature is not useful to you. Secondly, Shelly power monitoring modules do not allow for “dry contact” control.  What’s that? Glad you asked…

Shelly "Dry Contact" Relays

What is a “dry contact”? A technical term for a rather easy concept that is actually somewhat difficult to explain! In short, a “dry contact” (also known as a voltage free contact or potential-free contact) is where the power supplied to a switch (or in this case, a Shelly relay module) is isolated from the voltage/load being switched on and off. I told you it was not easy to explain, perhaps a picture truly does speak a thousand words…

Shelly Dry Contact

As you can see in the diagram, the Shelly 1 Plus is being powered by 240V AC – yet it is switching the Live (Active) wire from a 24V DC circuit. It can do this because the power being supplied to the module is completely isolated from the load being switched.

This ability to isolate input voltages (even AC / DC power) from the output (or “throughput” is perhaps a better word) makes Shelly dry contact modules very versatile – Suitable for a variety of electrical applications that would otherwise be difficult or  even impossible.

IMPORTANT: Do not, under any circumstances perform your own electrical work. Always use a licensed electrician.
Shelly Garage Door Control

A real world example… Garage door and gate motors can typically be controlled via wires connected to two terminals on the motor’s electronic-board.  One of these terminals outputs a 24V DC L (+) signal – the other terminal waits to receive the 24V current from the terminal above. Once detected, the garage door or gate is triggered to open or close.  By connecting the Shelly 1 Plus to these terminals, you can control your garage door or gate motor via your smartphone – from anywhere.

Shelly Relay Control Channels

Simply put… control channels refers to the number of independent loads a shelly module can control.  The Shelly 1 Plus can control one connected load, the Shelly 2PM Plus can control two seperate loads, the Shelly Pro 3 controls 3 loads and you guessed it… the Shelly Pro 4PM controls 4 connected loads.
Shelly 4PM Pro - 4 Channels

Shelly (Blind & Awning) Motor Control

The first thing we need to do is clarify “motor control”.  In the context of this blog, we are really talking about blind and awning motors. And not just any type of open / close motor… to work with home automation, we need a specific type of motor – known in the industry as 240V “dumb” motors (such as the Somfy LS40 below).

Dumb motors have 3 wires (sometimes 4 with an Earth wire) – 1 x Neutral wire and 2 x Active wires (one each for up and down).


I cannot stress enough how important it is to select the right blind / awning motors if you want to incorporate them into your home automation system (rather than using a stand-alone app).  Two wire motors (with simple Active and Neutral wires) are not compatible with Shelly modules.  If in doubt, please contact us before selecting your blind motors – we are always happy to help with free advice.

Shelly Dimmers

Shelly Dimmer Modules

Unlike the Shelly Relay modules above (that simply turn electricity on/off to the connected device), Shelly Dimmer modules can also dim / brighten the connected load (as well as on / off control of course) – this means they are only suitable for lighting control. There are two Shelly modules that are capable of dimming lighting…

Shelly Dimmer 2

Control a wide range of halogen lights, dimmable LED and ferromagnetic transformers with the smallest WiFi-operated dimmer in the World – Shelly Dimmer 2 can also work without a neutral wire and connects to your wall-switch so you maintain manual control.

Shelly Dimmer 2 - FAQs

Below are some of the most common questions we receive about the Shelly Dimmer 2 – if you cannot find an answer here, please feel free to contact us – we are always happy to help.

No. Do not, under any circumstances perform your own electrical work. Always use a licensed electrician.

If they are dimmable, then yes - Shelly Dimmer 2 should work. From halogen and incandescent bulbs to dimmable LEDs.

No. All attached bulbs / transformers must be the same type and wattage.

Shelly Dimmer 2 withstands a maximum load (combined wattage of all lights connected to the module) of about 210 watts and can only be powered by alternating current (AC) with a voltage between 110 and 240 volts.

Yes, Shelly Dimmer 2 has been designed to work without the need for a neutral wire.  In some cases (mainly for lower wattages), the Shelly Bypass may be required.

Yes. You will still maintain manual on/off wall-switch control as well as smart control. If you would also like to dim / brighten from the wall-switch, you can ask your electrician to replace your standard switch mechanism with a "momentary bell press" switch (i.e. Clipsal Impress Momentary Bell Press Mech). This will allow for on / off control (press and release) as well as dimming / brightning (press and hold). This is completely optional - at the very least you will be able to turn on / off the light from your existing switch and dim via smart control.

Yes - and you only require one Shelly Dimmer 2 and your existing wiring should not need to change.

Shelly RGBW2

Install Shelly RGBW2 and you will be able to control your LED strip lights with just one tap via your smartphone – or with your voice. It can control 12V DC (144W total) / 24V DC (288W total) RGB+W colour strips – or independent control or 4 single colour LED strips.

Shelly Energy

Shelly Energy Monitoring

They say knowledge is power! Well when it comes to energy efficiency, knowledge will certainly help you save power – and money! Shelly energy monitoring solutions have been shown to help reduce your carbon footprint and monthly energy bills by up to 40%!

All Shelly devices that include “PM” in their name support “Power Monitoring” (i.e. Shelly 1PM Plus). This means that you can not only control the attached load, you can also measure how much power it is using. This is great for individual lights or appliances – but what if you want to measure ALL the energy your home or business uses?  Or how much your solar is producing? Let me introduce you to two Shelly devices that will allow you to do this… and more.

Shelly EM - Energy Meter

Individually monitor the consumption of any of your home appliances, electric circuits and office equipment (lights, sockets, security systems, heating and cooling, etc.). Monitor consumption of your whole home or generated electricity from solar panels with a one of its kind WiFi-operated energy meter with contactor control functionality. Includes 50A clamp that is simply placed around any power cable to measure the current. Add an additional clamp to monitor a second electrical circuit.

Shelly 3EM - 3 Phase Energy Meter

Shelly 3EM is a smart Wi-Fi 3-phase professional energy meter that will help monitor electricity usage in real-time and get notified in case an appliance or system consumes power above a pre-set threshold. Additionally, it allows for contactor on/off control. Professional DIN Rail mountable and includes 3 x 120A energy metering clamps (one for each phase). Monitor a 3-phase circuit or 3 seperate circuits independently.

Shelly PRO 3EM is a professional DIN rail mountable three-phase energy meter. Enhanced with all the Shelly gen2 firmware flexibility and LAN connectivity, it can work standalone in a local LAN and/or Wi-Fi network. The Shelly PRO 3EM reports accumulated energy as well as instantaneous voltage, current, active and apparent power per phase in real time. It stores data in non-volatile memory that can be retrieved for a period of up to 60 days in 1-minute intervals. 3 x 120A or 400A clamps included (one for each phase).

Shelly Sensors

Shelly Sensors

Shelly sensors monitor environmental conditions around your home and allow you to create simple or complex automations based on these readings. With Shelly, you can monitor for motion, temperature and humidity, doors or windows opening and closing and more.

Shelly sensors allow us to create true home automations – where things happen automatically, without needing to touch your phone or say anything to your voice assistant. This is where the power or a true smarthome shines. From triggering simple automations using some of the Shelly devices above (such as lighting or even irrigation systems) to securing and protecting our homes from intruders or water leak damage… Shelly sensors open a up World of possibilities…

Shelly Motion Sensor 2

Shelly Wi-Fi Motion Sensor 2 is an always connected Wi-Fi Motion Sensor, equipped with the world’s lowest power-consuming Wi-Fi modem and powered by Silicon Labs Wi-Fi IoT Solutions. Featuring a 6500 mAh rechargeable battery with over 1 year battery life. The new Shelly Motion 2 is smaller and sleeker than the original Shelly Motion, and also includes a temperature sensor in addition to lux and vibration sensors.

Shelly Door / Window Sensor 2

Shelly Door & Window Sensor 2 with LUX measurement is designed to detect and report the opening and closing of doors and windows and trigger pre-set actions accordingly. Its compact design allows it to be easily installed on any door, window, safety gate, garage door, etc. And because of its lightweight minimalistic design, it easily fits into any interior design.

Shelly Flood Sensor

Shelly Flood is a smart Wi-Fi water leak detector with temperature measurement that will help you stay aware of any unexpected leaks, as well as temperature fluctuations, no matter how far from home you are. No wiring, easy control, and compatibility with other Shelly devices in your home network make Shelly Flood the best smart addition to your home safety.

Shelly Plus Addon

Shelly Plus Add-on is a galvanically isolated sensor interface for all Shelly Plus relays (i.e Shelly 1 Plus). Use it to measure temperature and humidity using its 1-Wire terminals, or connect various analog and digital sensors (temperature, moisture, reed switches, etc) for smart monitoring and automations. Shelly Plus Add-on is also  compatible with most Arduino sensors!

Shelly Remotes

Shelly Remotes

Shelly remotes allow you to trigger your Shelly devices – either individually or as a group (scenes). Best of all – you are in total control… using the Shelly Cloud app, you can create a scene that turns off all of the lights in your home (provided they are connected to Shelly lighting modules)… all with a single press of a button. Of perhaps you would like to turn on the spa pump, open all the lounge room curtains… the possibilities are almost endless.

Shelly offer a few different remote options that offer quick and easily accessible convenience that is always at your fingertips – without needing to use your smartphone or voice assistant…

Shelly Wi-Fi Button 1

Original price was: $59.00.Current price is: $38.00.
Shelly Button1 allows you to activate scenes with a combination of different devices. Just set your push sequence on the Shelly App and choose different scenes with a set of actions; for example, click once for ‘Good morning’ to open blinds and turn on the coffee machine first thing in the morning. Click twice for a ‘Movie night’ and enjoy colourful light with Shelly RGBW, completely changing the atmosphere, or three times for a ‘Good night’ scene, closing the blinds and turning off all the lights in the room.

Shelly Plus i4 Wi-Fi Input Controller

Original price was: $39.00.Current price is: $23.00.

Shelly Plus i4 allows you to manually activate or deactivate any created scene, run synchronised actions, or execute complex trigger scenarios. You can use Shelly Plus i4 to control other connected Shelly relays, sensors, or HTTP and MQTT-controlled devices. Small enough to fit behind every wall switch, Shelly Plus i4 can show the status and control the action of four inputs. Simply press one of the connected switches and watch your scenes and smart home come to life. Available in AC or DC models.

One thought on “An introduction to Shelly Wi-Fi smart devices

  1. Anthony J Clarke says:

    Great article, thanks. After purchasing HomeyPro from you I am having more success with these devices than any other Zigbee/Zwave devices. Would be great to update it with the newer products and the gen3 models of some of these relays

Leave a Reply

Your email address will not be published. Required fields are marked *

11 + four =