Shelly is not a familiar name for every smart home enthusiast in the United States, but it is an established brand in Europe and other parts of the world. Doug Roberson, CTO of Allterco Robotics US, provided me with some Shelly products for testing.

Shelly smart home products are manufactured by Allterco Robotics, one of seven companies that make up Allterco, a holding company headquartered in Sofia, Bulgaria. Allterco has 20 years of experience in mobile, value-added products and services. The company is expanding beyond the telecommunications industry and is now focusing on the development and distribution of IoT products and solutions.

Allterco Robotics launched the Shelly series of smart home IoT products in 2018. These products are sold in 120 countries around the world and an office will be opened in the United States in 2020.

Shelly 1: Provides control of a single circuit through its internal relay

Shelly 1PM: Provides control of a single circuit through its internal relay, and can measure the power used by lights/appliances connected to the controlled circuit

Shelly 2.5: Provides control of two circuits through its internal relay, and can measure the power used by lights/appliances connected to the controlled circuit

Shelly EM: ​​Provides power measurement of up to two circuits by using the clamp on the current transformer, and can control the relay connected to its contactor control terminal. The relay can then control a circuit connected to any number of lights/appliances.

All of these are very small and compact IoT devices. In fact, each of them is as big as two Oreo cookies stacked on top of each other!

Shelly 1, Shelly 1PM, Shelly 2.5, and Shelly EM are all connected to an 802.11 b/g/n network via Wi-Fi, and have an internal web server for configuring and operating the device using a browser. Each device can also be operated and configured using the following:

More information about these APIs and third-party smart home systems integrated with Shelly devices is provided below.

In addition to the basic functions of turning on/off relays and measuring power, each device also has many very useful built-in functions

Each relay can be configured with automatic opening and automatic closing timers. Whenever the relay is turned off, the auto-on timer will automatically turn on the relay after the specified number of seconds. Similarly, the auto-off timer will automatically turn off the relay when the relay opens after the specified number of seconds. This is very useful if you use Shelly 1 PM to monitor the power used by refrigerators or freezers. In this case, the relay should never be turned off, as this will cut off the power to the device. Therefore, it can be programmed to automatically reopen when it is accidentally closed. Some electrical appliances may be damaged due to power failure and immediate re-opening. In this case, it is very useful to be able to delay the reopening of the relay.

The relay can be configured to turn on when power is restored, turn off when power is restored, or return to the settings when power was lost. For example, if you use Shelly relays to control lights in your home, this will be very useful.

After the power outage started early in the evening, it is not advisable to suddenly turn on the light at 3:00 AM when the light is turned on. Or, if the relay is used to monitor the power supply of a refrigerator or freezer, the relay should always be on when the power is restored after a power failure.

The built-in scheduler allows the relay to be turned on or off on a specified day of the week, sunrise or sunset at a specific time. For example, Shelly relays can be used to turn on external lighting at sunset every night of the week. The scheduler can then turn off the external lighting at 10pm on weekdays and at 11pm on weekends.

This function optionally requires a username/password to control the device.

Connect the device to the SNTP server of your choice so that its internal clock is always accurate, and the scheduled event will occur when you expect it. Shelly devices can also automatically detect the correct time zone they are in. If the automatic detection fails to correctly identify the correct time zone due to the homeowner’s Internet connection routing method, you can also manually configure the time zone.

You can specify a backup Wi-Fi network for the device in case the main Wi-Fi network fails.

The Shelly smartphone application also provides the ability to create groups and scenes. The group allows multiple Shelly devices to be controlled at the same time. Scenarios can provide more complex automation, although they do require devices to be connected to the Shelly cloud.

The Shelly scenario first defines the "when" conditions that will trigger the scenario. The scene can be:

Once the "When" condition is defined, you need to define the "Do" operation that will be performed. There are many possible operations:

Finally, you can define an active time for the scene so that it may only be active on certain days of the week and certain times of the day.

As you can see, Shelly provides a lot of features out of the box without requiring users to connect their devices to smart home processors or hubs. More detailed information about Shelly 1, Shelly 1PM, Shelly 2.5, and Shelly EM are provided below.

Shelly 1 is the most popular product of Allterco Robotics. It is a very small and compact IoT relay switch.

Shelly 1 has a very flexible design. It is the only Shelley relay that provides dry contacts. In other words, the internal relay simply connects/disconnects the two terminals on Shelly 1, and no voltage is applied to them.

Shelly 1 can be powered by 12 V DC, 110 to 240 V AC, or 24 to 60 V DC. You only need to select the voltage used to power Shelly 1 by moving the jumper between the three pins on the device, and you can access these pins by removing the small rubber cover on the manhole.

By default, the jumper settings are 110 to 240 volts AC and 24 to 60 volts DC operation. The jumper needs to be moved only when Shelly 1 is powered by a 12V DC power supply. Shelly 1’s internal relays are rated at 15 amperes in the United States, which matches the standard circuit breakers used in homes.

There are five screw terminals for connecting wires to Shelly 1:

As mentioned earlier, Allterco Robotics has a wealth of functions built into its Shelly relays, so they can be used in various applications in smart homes. Here are just a few examples:

First, you can use Shelly 1 to convert basic lights to smart lights. You can also connect the wall switch to the switch input of Shelly 1 and the O and I terminals of the lighting load to convert the light switch into a smart switch. The "button" input on Shelly 1 can be configured in many different ways to provide the best user experience. For example, it can be configured as an "edge switch", so every change of the switch (on to off or off to on) will cause Shelly 1 to change the state of its relay.

In this configuration, if the switch connected to Shelly 1 is in the on position and someone uses the Shelly application to turn off the connected load, when the switch is switched from on to off, it will turn on the load again. This avoids the user's confusion that nothing happens because of flipping the connected switch.

Shelly 1 supports the separation of button input from its internal relay control. In this way, the Shelly 1 relay can be connected to the lighting load, and the lights can be controlled through the Shelly application, Shelly 1's network client, smart home processor/hub, etc. Then there is the wall switch (previously controlling the light), which can be connected to the button input of Shelly 1 to control any desired function in the smart home.

For example, in multiple groups of switch boxes, the switches can be configured to control different lighting scenarios instead of a single light initially connected to them. If you want to do this, it makes more sense to make the switch used to select the scene a momentary switch instead of an on/off switch. Although I have never tried it myself, there are some YouTube videos describing how to convert a Decora-style wall switch into a momentary push button switch. You can find one here.

The O and I terminals connected to the Shelly 1 relay can be connected in parallel with the wall-mounted controllers on most overhead garage door openers, making them smart door openers. It should be noted that when the garage door is closed remotely or automatically without being present, it is very important to provide audible and visual warnings to ensure its safety. For more information on this, you can check out my article on making your garage smart here.

Any standard safety sensor that provides dry contact closure can be connected to the button input on Shelly 1. Shelly 1 can then be integrated with a smart home processor/hub, which can be used to trigger smart home operations based on, for example, when someone enters a room, the opening/closing of the door or the motion sensor is triggered.

Similarly, the O and I relay terminals of Shelly 1 can be connected to the zone input on the traditional security system and trigger the zone when an event detected by the smart home processor/hub occurs. However, it is important to remember that the safety system has undergone extensive testing and certification to ensure that it is 100% reliable. People's lives depend on a security system. When an intruder enters their home, if there is a fire, or other important events occur in and around the home that the security system is designed to sense, the security system will notify them. Smart home products are not subject to the same strict restrictions, and this needs to be kept in mind when using smart home technology to enhance security systems.

Shelly 1 and Shelly series relays/switches are very versatile devices. Their use in smart homes is only limited by the imagination of the homeowner.

Shelly 1PM, like Shelly 1, can turn on/off a single load. However, it differs from Shelly 1 in several important ways:

There are five screw terminals for connecting wires to Shelly 1PM:

Like Shelly 1, Shelly 1PM can be used in multiple ways.

Shelly 2.5 is essentially two Shelly 1PM stuffed into the same size package. Similar to having two Shelly 1PMs, it can independently power on/off the O1 and O2 terminals on the device. It can independently measure the power consumed by each device being controlled. And, like 1PM, it includes internal temperature protection. 2.5 monitor its own internal temperature, if the consumed power makes 2.5 overheat, you can turn off the equipment it controls.

Like two 1PMs, it provides independent power overload protection for each device connected to it. If the power consumption of the device exceeds a user-defined threshold, 2.5 can shut down any device under control.

Like 1PM, 2.5 can be powered by 110 to 240 volts AC or 24 to 60 volts DC. Similarly, unlike 1PM, it cannot be powered by 12 volt DC. The maximum load of each channel is 10 amps.

There are seven screw terminals for connecting wires to 2.5. The terminals marked L and N are used to power 2.5. There are two L terminals on 2.5. Unless the total load of the equipment controlled by 2.5 is greater than 15 amps, you only need to supply power to one of them.

The terminals marked SW1 and SW2 are used to connect the switch to 2.5. The other contact of each switch is connected to the wire that supplies power to the L terminal of 2.5

The terminals marked O1 and O2 are connected to the internal relay of 2.5 and are energized when the internal relay is closed. These are used to connect loads that will be controlled by 2.5.

The complete wiring diagram for 2.5 can be found here.

As mentioned earlier, Shelly 2.5 is essentially two 1PM in one shell. However, the uniqueness of 2.5 is that it can be configured as "roll-up mode" in the device's settings.

In the rolling shutter mode, 2.5 is used to control the electric curtain or any dual-input motor; one input makes the motor move in one direction, and the other input makes the motor move in the other direction. In this case, the O1 terminal of 2.5 is connected to one motor input and the O2 terminal is connected to the other.

Then, the rolling shutter mode interlocks the 2.5 O1 and O2 outputs, so the two cannot supply power to the sunshade motor at the same time. Second, it enables 2.5 to accept the use of up, down, and stop commands. When the up command is sent to 2.5, the relay fed to the O1 terminal is closed and the O1 terminal is energized, so it can power the motor to lift the curtain. When the down command is sent to 2.5, the relay supplying the O2 terminal is closed and the O2 terminal is energized, so it can power the motor to lower the curtain. Finally, when the stop command is sent to 2.5, both relays are turned on.

When 2.5 is in the rolling shutter mode, there are other settings available. First, you can set a working time, 2.5 will automatically stop all actions after the preset time period. Second, you can set power-off limits. 2.5 The power used by the curtain motor will be monitored. If the motor exceeds this limit, all movements will be automatically stopped. When the motor-moving device reaches the stroke limit or there are obstacles that hinder the device's movement, the power consumption peak of the motor usually occurs.

Although 2.5 can be used to control electric curtains, there are many other electric devices that can be used to control:

Shelly EM is a completely different device from Shelly 1, Shelly 1PM and Shelly 2.5. It uses a clamp-on current transformer (CT) to provide power measurements for up to two circuits. Shelly can provide 120 or 50 amp CT for power measurement using EM. The choice of which CT to use will depend on how much energy the monitored device will use. For example, if EM will be used as a whole-house energy monitor in a house with 200 amp service, larger CTs will be needed because they will be placed on the "power" that powers the entire home. If EM is only measuring the power used by a single device, a 50-amp CT is sufficient.

EM has a contactor output. It has a rated current of only 2 amperes and is designed to drive a relay, which can then be used to control lights/appliances that consume more power.

Another difference between the EM and the other devices described earlier in this article is that the EM can only be powered by 110 to 240 volts AC. This device does not support DC power.

Like 1PM and 2.5, EM has an internal temperature sensor. However, the latest firmware does not yet support over-temperature protection. I was told that it is under development and should be available through firmware updates in the future.

EM has independent over-power and under-power thresholds, which can be set for each CT. If the over power threshold of Shelly Ems is exceeded, the output can be automatically turned off. However, EM does not have hardware-level overcurrent protection like 1PM and 2.5.

There are seven screw terminals for connecting the wires to the EM:

The obvious use of EM is to measure the power used by one 240 VAC device or two 120 VAC devices, and then use these measurements as part of an energy management plan. It can also be used in many ways that I described at 1pm, including making stupid devices smart. Using over-power and under-power threshold URL operations, a message can be sent to the smart home processor/hub so that it can notify the homeowner that, for example, their clothes are dry and will wrinkle if they are not removed from the dryer .

Allterco Robotics provides a fully documented API for the entire product line. Shelly IoT devices have been integrated with the following smart home platforms:

Some of these integrations take advantage of the ability of Shelly devices to communicate using MQTT. MQTT is an industry standard messaging protocol for communication between IoT devices.

Drivers for Crestron, Savant, Control4 and RTI smart home platforms are also under development.

For testing purposes, I wrote a basic Crestron driver that utilizes the local control REST API. The driver I wrote supports the opening, closing and switching commands of Shelly 1, Shelly 1PM, Shelly 2.5 and Shelly EM. When Shelly 2.5 is configured in roller blind mode, it also supports Shelly 2.5 to control electric curtains and read power measurements from Shelly 1PM, Shelly 2.5 and Shelly EM.

I expect the functionality of the Crestron driver Allterco Robotics currently under development will be more comprehensive. However, before you are ready, you can find the driver I wrote on GitHub here.

Shelly relays are based on the industry standard ESP8266 Wi-Fi microchip. Therefore, in addition to each of the above integrations, the Shelly device also includes a port that hobbyists can use to flash the device with spare firmware. An alternative that is popular with smart home enthusiasts is the Tasmota open source firmware.

The first thing you need to do is to download the Shelly app from the Apple App Store or Google Play Store. You need to create an account and provide typical permissions for sending notifications, etc. The application also requires location permissions. This way it can decide whether to communicate with your device through a local API or a cloud API. You can also choose whether to enable cloud access to the device. If you disable cloud access, you will not be able to remotely access the device through the application and the historical power data collected by Shelly Cloud from its device.

When you use the application for the first time, it will go through a loading process. I waited for a few minutes, and then guessed that there might be a problem. I restarted the application, and then it immediately appeared and started working. I have reported this issue to Allterco Robotics. It's no big deal, it's just something to be aware of.

Once the Shelly application is up and running, I add Shelly 1, which I am testing, to the application. I connected the power cord to Shelly 1 and plugged it in. Then I launched the application and selected "Add Device". I was prompted to provide the password for the Wi-Fi network, and then provided a list of all the different Shelly products. I chose Shelly 1, and was prompted to join Shelly 1’s local network. Then, the application configured Shelly 1 and added it to my home network.

The next step is to create a room in the app where you will install one or more devices. You can provide the name and picture of the room. You can upload your own picture or choose one of the two default pictures provided in the app; living space or bedroom.

After defining the room, you can add devices to the room. First, you need to provide a name for the device and select an icon. Each device in the room has an icon, and you can choose from 16 options. Then you can choose how the device is used; as a relay to control certain devices or control lights. This will not affect how the device operates when controlled via the Shelly application or the local REST API. However, it does affect how voice assistants and smart home hubs that interact with Shelly devices through cloud APIs will be used with Shelly devices. Finally, you can choose which room the device will be located in. You can select any room you create, or you can set it as a hidden device that is not exposed in the room for on/off control.

After defining the room and adding the Shelly device to it, the app can configure or control the device very easily.

If you happen to work in front of a computer, the Web interface of the Shelly device is another very convenient way to configure and control. However, you only need to note that you can only use the product's application to configure or create the groups and scenarios described earlier.

It should be noted that users need to regularly check the Shelly application or web interface of each device installed in their home to see if there is a firmware update available. The device will not download and install firmware updates on its own.

The small size of the relays makes them very convenient to use. They are designed to be installed in a single group of electrical boxes, so they can be used to automatically operate switches or sockets. When you consider the space taken up by the wires in the box, it can be a bit crowded. However, this is no different from when a smart switch or socket is installed.

Once the wiring is in place, the Shelly device is operating well. Although I encountered some glitches in the application, the devices themselves are 100% reliable. I have never encountered a situation where the device cannot respond properly to commands or goes offline unexpectedly.

When you write a driver to integrate with the product, you can get a more detailed picture than just performing some basic tests. I found Shelly 1, Shelly 1PM, Shelly 2.5 and Shelly EM to be excellent products. The fact that I have listed many areas of improvement should not be considered a criticism of the product. This really means that I see the huge potential of smart home products and want more.

1) Shelly's native REST API is a popular feature that allows devices of this brand to be directly integrated with smart home processors/hubs so that the devices will not become stupid when the Internet is interrupted. However, there are some holes in the API that need to be filled. Shelly provides URL callbacks, so, for example, if the device is controlled through its application, an HTTP call will be made from the device to the smart home processor/hub to make it aware of changes in the device state. This is very effective, but unfortunately, there is no URL callback available for all properties of the device.

Most notably, there are no URL callbacks to report changes in the power consumption of devices connected to Shelly 1PM or Shelly 2.5. The smart home processor/hub integrated with these Shelly devices must constantly poll power to implement smart home operations, such as sending notifications when the washing machine is completed or monitoring whether the refrigerator or freezer suddenly stops running.

The smart home processor/hub must poll Shelly 2.5 in rolling mode to get the location of the shadow, because its URL callback is not reported.

The Shelly Duo bulb (not included in this article) does not contain any URL callbacks at all, so it cannot integrate seamlessly with smart home processors/hubs without the need for continuous polling to keep its status up to date.

2) The internal relays of Shelly 1, Shelly 1PM, Shelly 2.5 and Shelly EM provide normally open contacts. When the "open" command is sent to the Shelly device, it will power the relay internally to close the contacts of the relay, thereby completing the circuit of the device connected to it.

Although relays are very reliable, they are electromechanical devices that will eventually fail. It would be better if the normally open contacts and normally closed contacts from the internal relay are exposed on the terminal block of each Shelly device. For example, if Shelly 1PM is used to monitor the power supply of the refrigerator, the relay does not need to be continuously powered because the refrigerator can be connected to the normally closed relay terminals of Shelly 1PM. In this way, even if the Shelley device fails, the refrigerator can continue to supply electricity, and the stored food will not be at risk of deterioration.

3) There are some challenges when using Shelly EM to monitor the power consumption of home appliances. When the power consumed by the monitored device exceeds or falls below a defined threshold, it can trigger operations that exceed and fall below the URL. If the only requirement is to send a notification when, for example, a washing machine or dryer is completed, over and under URL operations are a good solution. However, there is one thing to understand about the over-power and under-power URL operations on Shelly EM.

Each channel has independent URL actions, and they cannot be triggered based on the total power consumed by 240 VAC. It would be great if there was an option to simply add the power of channel 2 to channel 1. The existing URL action for channel 1 can then be used to notify the smart home processor/hub, based on the total power consumed by the 240 VAC device.

If you really want to use Shelly EM to trigger a notification when a 240 VAC device (such as a clothes dryer) completes its drying cycle, you may find a viable solution by simply monitoring a single branch dryer that is fed to 240 VAC . If you do this, you will have to see which leg can better measure the operation of the device. On my own clothes dryer, the power consumed by one leg periodically drops to zero, while the other leg never drops below a few hundred watts.

I want one leg to only power the heating element, and when it cycles off periodically, the power consumption drops to zero. The other leg might include powering a constantly running motor to rotate the drum of the dryer and provide a better indication of whether the dryer is running.

4) Most electrical boxes in homes installed behind switches and sockets today are made of plastic. This is ideal for installing Shelly devices into it, because plastic does not significantly weaken the Wi-Fi signal strength. This is not the case for metal circuit breaker panels where Shelly EM may be installed. If the circuit breaker panel is installed in a basement or garage, it may be far away from the Wi-Fi router in the home. This will make it difficult or impossible for Shelly EM to connect to the home Wi-Fi network. It would be great if there is a Shelly EM version that includes an Ethernet port to solve this situation.

5) Although Shirley 1, Shirley 1PM, Shirley 2.5 and Shirley EM may be designed to be tucked into a small plastic electrical box behind a switch or socket, sometimes this is not practical. For example, they may be installed in large electrical enclosures with DIN rails or structured media cabinets. In this case, in order to keep the installation clean and orderly, there should be a way to install the Shelly device on a flat surface.

This can be achieved by adding some screw pieces to the Shelly shell (you can quickly trim if not used) or by including a hole in the shell through which the screws can pass. Similarly, it would be nice to have a small flexible cover, for example, to cover the voltage selection port on Shelly 1 to cover all screw terminals on Shelly devices. This will eliminate the chance that anyone accidentally touches these terminals and receives an electric shock or accidentally touches the non-insulated grounding wire in the electrical box.

6) Shelly 1PM, Shelly 2.5 and Shelly EM include Wi-Fi status light. It would be great if this was also included in Shirley 1.

7) There should be a notification function to notify the homeowner when a firmware update is available for their device or an option to automatically install the firmware update. If the Shelly device is integrated with a smart home processor/hub, the homeowner may never use the Shelly app or the device's web interface to realize that a firmware update needs to be installed. Firmware updates may include important security patches. If these patches are not installed, the homeowner may be at risk of being attacked by hackers using their equipment.

In general, I found that the Shelly device is very easy to use, responds very quickly to commands sent using the local REST API, and is reliable. Their design makes them very flexible and can solve various problems in smart homes. Moreover, although there were some glitches when using the Shelly application, Shelly 1, Shelly 1PM, Shelly 2.5 and Shelly EM all worked well during my testing.

Their small size makes these devices ideal for installation in electrical boxes behind household switches and sockets. Or, to turn a lamp purchased in a department store into a smart lamp, you can install it in the lamp holder. All this makes these devices ideal for creating smart homes, where all the technologies are hidden from sight and will not take over the decoration of the home.

In addition to the uses of these products I outlined above, professional smart home integrators may use them in other ways. Unlike most smart home hubs, smart home processors are equipped with relays. These become very valuable resources, because if you need more relays than the manufacturer provides, adding them can cost hundreds of dollars. This is also the case when a relay is required in a location different from the location where the smart home processor is installed. Shelly relay is the ideal solution to solve this problem, and the cost is very low.

In addition to being used by professional smart home integrators, Shelly 1, Shelly 1PM, Shelly 2.5 and Shelly EM are mainly products for more advanced smart home enthusiasts. Not because they are not very useful and of low quality, but simply because they must be connected to the circuit. You either need to have this level of knowledge, or hire someone with professional knowledge to do this for you; this will significantly increase the cost of homeowners using Shirley products. Shelly does produce a series of plug-and-play products that ordinary consumers can install themselves, including Shelly Plug and a series of smart bulbs. However, Shelly 1, Shelly 1PM, Shelly 2.5 and Shelly EM all require a certain degree of electrical wiring knowledge to use, and many people do not have it.

Jay Basen has been a home automation enthusiast for more than 30 years and has worked in the industry professionally for nearly 20 years. His professional background is electrical engineering and software development. He has a master's degree in engineering and has been engaged in professional software writing for more than 40 years. To read more articles by Jay, please visit his blog http://topicsinhomeautomation.blogspot.com/

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