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#45: First look at the new Shelly Pro 4PM

Note: I’m still writing this page, but I wanted to get the video up quickly because the Shelly launch event is only a few hours away!

For years I’ve been running my home automation switchboards using “temporary” controllers using Ethernet-enabled Arduino boards controlling DIN-rail mounted relays. My hope was that some day, someone would release a DIN-rail mounted control system with wired connectivity.

And now, all these years later, Allterco have done it. The new Shelly Pro 4PM looks like exactly the device I’ve been waiting for.

Disclosure: Allterco sent me this pre-release unit free of charge. However, I have personally paid for Shellys in the past and I’m sure I will in future. They had no input into this video, which is my own honest assessment of the Pro 4PM.


MQTT control

The Shelly Pro 4PM supports MQTT control out of the box. All you need to go is go into the MQTT configuration menu, put in the details for your broker, and it will be ready to go.

The MQTT topics are based on the device ID of the specific Shelly module, but converted to lower case. You can find the ID by opening the web interface and looking at the bottom:

The topic for sending commands to the Shelly is of the form:


So based on the device ID in the screenshot above, you can see the command topic would be:


Messages are sent and received as JSON. To turn on an output, send a message to the command topic of the form:

{"id":1, "src":"user_1", "method":"Switch.Set", "params":{"id":0, "on":true}}

This example turns on the first channel, because in the “params” section it has the ID set to 0 and the “on” value set to “true”. To turn off the first channel, change the “on” value to “false”.

Turn control the second channel, use the id “1”, and so on.

To see events published by the Shelly, including when channels change state and how much power each device is using, subscribe to the topic of the form:


8 thoughts on “#45: First look at the new Shelly Pro 4PM

  1. What does it cost

    1. It’s about EUR65, which makes it just over AUD100 at today’s exchange rate.

  2. Is it approved for use in Australia?

  3. Great information Jonathan, Thank you. I presume that you intend to use these SHelley devices in the “detached mode”. What is your fall back plan if the device loses connectivity?

  4. Hi John,
    There is a couple of disadvantages here. Like in your case with 2 switch boards you may need roughly 20-30 of these? 4 lights per device. Which is approx 2000-3000$. In addition you will need 20-30 ports on your switch, which probably means you need another 24port switch (~300$). Super house system will be 2-3 times cheaper.

    Checking power consumption and being able to turn the lights off/on from the device are cool features for sure, but how many times you really needed to do that?

    The biggest advantage of this system is that it’s much easier to setup out of the box. You don’t have to deal with arduino code and no need to assemble all the components – Arduino – relay drivers – relays.

    So If you asked me do I want to replace my Superhouse system with this one – I would say “probably no”, but if you asked if I want to use Shelly in the new house I would say “Maybe yes”

    What would be a really cool thing is if they also released 8-12-16 channel devices

  5. Another option is to mount each of these in a 4 pole plastic enclosure and hide them in cupboards closer to the lights being controlled then use the existing switch wires as the inputs as they are 240v.
    I have a few M-Elec stitchy units that do this making retrofit easy even for existing 2 way switching

  6. There are also, listed as coming soon, Shelly Pro 1 and 2 with and without power monitoring.
    They can be powered by 12V DC
    The models without power monitoring can switch low voltages
    I would like to see dimmer versions.

  7. Where can you buy them?

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