Shelly Plus PM Mini

Another in the Mini series from Shelly, the PM (Power monitor).

Update: explanation from Shelly: Easy, N is almost double the heat inside of the device. Sorry but in such small size we didn't want it. Double out allow to use single device in double socket which is most useful than second N.

Obviously this wants to be in-line with the device you are monitoring.

What struck me as odd from the pictures, and did confuse others as well, is that it has L/N (in) and O/O (out).

Is that L/N in and L/N out? That would make sense if it is to go in-line to a device being monitored.

No it is not!

As you can see, the O/O are both wired together and are the Live out after the monitor.

There is no second N, so wiring in this in-line either means two neutral in one screw terminal (not ideal) or a wago to join the neutral wires.

Why Shelly? Why?

I appreciate an L/N/gap/L/N may have been messy to track the neutrals, but what they could, very easily, have done have N/N/L/gap/O. This would allow live in and out, and neutral in and out and no wagos, and no two wires in one screw terminal. Way better.

I had to draw diagrams to explain to the people on the Shelly group on facebook!

How you have to wire it now

How it could have been

As explained above, the explanation is N through the device is extra heat, but to be honest I do not buy it.

The two O, meant that if one uses the second O only, all the current has to flow an extra few mm via a nice thick track to the second O terminal and that is extra resistance and heat. But surely that is exactly the same as would happen with N flowing to an adjacent N terminal the other side.

Shelly Plus 1 Mini

The new Shelly Plus 1 Mini is now available, and it is indeed tiny.

Note: Detailed instructions of upgrade from Shelly to Tasmota via web interface at the end of this blog.

Key differences from the Shelly Plus 1

• Smaller (33½mm x 28mm x 16mm)
• Cheaper
• No DC power
• No programming connections
• 8A not 16A relay

The lack of programming header was a concern as I have always reflashed these using the programming header - but it can be done via the web control pages.

I did try, and failed, to find an image of the back of a Shelly Plus 1 Mini - so here you are...

It does still have a dry contact relay, making it suitable for working DC contacts (garage door opener, etc).

It still has the button on the back.

It still has an LED in the back.

It does still have the ESP32 processor.

But overall, this is a welcome addition to the Shelly family.

Inside

The inside is indeed compact. As you can see, the back does have programming pads. I have not worked out what they are yet, but should not be hard.

Upgrade to Tasmota

These are basically the steps from https://github.com/tasmota/mgos32-to-tasmota32 but with some explanation of exactly which menus to pick at each stage.

1. You need to connect to the AP for the Shelly, and it does not pop up so you need to visit 192.168.33.1 to talk to its web interface.
2. Select "Configure Wi-Fi Settings", tick "Enable Wi-Fi network", select SSID and enter password, and "Save settings". You then have to work out what IP address it is on as it does not say - you may have to check your DHCP server.
3. You will need the right zip file. This lists them release section but on a mac you end up with an unzipped directory - you want the raw zip. Curl works with the link, but as they have a 302 you need curl with -L to follow the 302 and so make the valid ZIP file. Note they say you cannot load using a URL in the shelly upgrade menu for some reason.
4. On the Shelly control page on its new IP, select "Settings", "Firmware". If the Shelly is not itself on latest code, you may need to tell it to upgrade first.
5. On the Shelly control page on its new IP, select "Settings", "Firmware", and under "Upload custom firmware" selecting the zip file. Click "Update device". It should say (at top of page) "Your Shelly is updating...". Note, you need the right upgrade file for the model - it will not work if you pick the wrong one, e.g. don't confuse Plus1PMMini and PlusPMMini for example.
6. You then have to connect to the tasmota AP. Wait for it to auto load the set up page, select WiFi and enter password. It shows the new IP so you can get to it (probably the same as the Shelly got).
7. Important, it seems the following steps are necessary else it can be bricked on next update!
8. Select "Configuration" / "Auto-configuration" and pick the device and "Apply configuration". Again, get the correct device setting.
9. The next bit in the instructions was "Open the partition wizard" fooled me. It is "Consoles", "Partition Wizard". If not present then it is possible to upload a Partition_Wizard.tapp file under "Manage file system". Under the "Partition Wizard", select "Start migration". It says "Magic is happening" and there are "multiple restarts". Some intermediate steps will show "SAFEBOOT". It takes a few minutes to be ready.
10. Select "Consoles", "Partition Wizard", and click "Resize FS to max". This removes all files (including the Partition Wizard).

You now have an upgraded Tasmota installed Shelly, which is Matter compatible and works with MQTT.

And finally, the pin out for serial programming.

Do not dismantle or connect serial programming whilst connected to mains power!

With pogo pins :-)

Setting the temperature

My air-con can have a temperature set and aim for it.

• It has a wide range of ± a few degrees which I don't like.
• It is not setting temperature by me, it is basing it on some sensor it has.

To fix this I have used an environmental sensor - on my desk, and for my bedroom, on my bed head. I then control the air-con - telling it I want it higher or lower than it thinks things are, so as to aim for the right temperature by me. It works well most of the time and keeps the temperature very close.

That is my bedroom, last night (cooling), units in ℃, so maybe ±0.2 ℃ at most. Good.

I also have radiators for the winter, and they have the same fun, driving the valve on the radiator with some prediction.

Which to use for heating? air-con (heat pump) or radiator... Bearing in mind some of the house does not have air-con, so has radiators anyway. I don't actually know which is most cost effective / efficient. But I can choose. Have systems in place to make sure they are never fighting each other :-)

Per room radiator control

One of the key things is per-room controls - this means a temperature sensor in the room, and a radiator control, and some way to tell the boiler that one of the rooms needs heat. We have two heating loops (up and down), my daughter has two (left and right!). But for each radiator there is one boiler control that is needed.

The hard way

So, the hard way, I have my fancy environmental monitors with a display. They have a config for temp targets throughout the day. I have systems to override for empty rooms. Using the light switch marks a room in use for the day :-)

They talk MQTT to a Shelly running Tasmota that controls the radiator. So needs an MQTT broker.

The Shelly talks MQTT to a FireBrick to say radiator is on/off.

The FireBrick has a set of profiles, and any one in each loop will cause a message to another Shelly running Tasmota to operate the heating loop valve.

This triggers the boiler as needed.

It works.

It is not cheap or simple - the env sensors cost, the FireBrick costs a lot.

The easy way - maybe

So I am working on an easy way - my daughter happens to have a FireBrick, but even so I am trying to make a really easy way to do this. Not all of my kids have one (?!).

The first step is the reference temperature. A sensor that can be placed sensibly, e.g. by a bed.

I had found some nice industrial (BlueCoinT) ones at €31, but now have found, thanks to a recommendation, some stupidly cheap ones on Amazon. They are only £9, and even cheaper on AliExpress. They can be refreshed with sensible code.

The next step is controlling the radiator, and something like a Shelly Plus Mini would be ideal. Not sure of price yet, but the normal Shelly Plus 1 is £16.49. Whoa, they used to be less than that! Interesting. The Mini may be less. We'll see. But up to under £26. The radiator control itself is something like this, £19.63

So yes, we are up to £45 per room. A few more £s for back box and fused spur box for the Shelly mini by the radiator. And one Shelly at the boiler.

The comms can all be BLE. Sensor to Shelly, and Shelly to boiler control Shelly. Just needs a bit of software.

Not ideal, but £50 per room for exact per room heating control is probably quickly worth it. Simple web interface (or maybe even HomeKit) for unoccupied rooms, and controls for times of day and target temperatures via a web page. This can quickly save on heating costs and make things more comfortable.

It always amazed me people ran their house with one thermostat on the wall in the hall.

To USB or not to USB, that is the question!

I have done quite a lot of small boards now, as I have blogged at various points.

It has helped me build up my skills in circuit and PCB design, and over time I have moved to different approaches for things as I have learned. Some things driven by practical usage, some by cost, some by simplicity.

At present I am working on ESP32 based boards, and I may yet move on to ESP32-S2 or ESP32-S3, at least one of which does some direct USB, but for now, for ESP32, I need serial connection for programming and debug. The ESP32 are especially appealing in the form of the ESP32-PICO-MINI-02 module which has extra flash and RAM which is invaluable.

I have "standardised" on a USB-C connector for my boards, where needed, for simple power. That is most boards, e.g. this LED strip controller.

It uses USB-C for the 5V supply for the LED strip, and via 3.3V regulator for the ESP32.

In many designs, I have included an FT231XQ USB UART in the design, allowing not just power, but programming and debug via the USB-C connector. This works really well. It makes it very simple to develop on. I have even learned my lesson with diodes on boards which can also have 12V DC, and USB connecting both at the same time :-)

But the FT231XQ is not a cheap part, and not a readily available part (a lot of parts are now available after COVID, but some still in very short supply). So I have been making even these boards have an alternative for when the FT231XQ cannot be fitted.

Indeed, I have actually started making boards which have no FT231XQ at all, even if they have a USB-C socket for power (like the one shown above).

This means I need some sort of header. One of the reasons I went with the UART in the first place is any sort of sensible header connector would take as much board space as the UART chip, and add cost or time, especially if a through hole connector.

But, the way Shelly do it has come to the rescue. They use a small 1/10" 5 pin header (and a 1/20th" 7 pin header) - a socket on the board, and I made this to work with them. These are useful if you are wanting to reprogram Shelly with say tasmota, or for any projects with similar devices. See Amazon.

It has header pins for the 5 and 7 way connectors. The shelly has a proper socket for these.

However, I can simply make the board have holes, instead of a proper "header", like the 5 holes on this boards.

I can simply push the pins in the holes, and hold them whilst programming. Indeed, if I can get the holes just right they will fit firmly enough not to need holding and so can be used for debug as well. It is cheap - holes don't really cost anything. It does not take a lot of space, especially as it can (like that example) be under another connector even.

I am working on slight variations of the holes, to try and make a firm fit to the square pins. The latest is slotted holes. In practice this means each set of boards I get has a slight improvement and I try it. The above design had holes slightly too small - some boards needed to be "held" whilst programming (which is not really a problem, but adds some time). This is my latest design for them.

So it is a question of whether I bother with a UART on future boards. Using USB-C for power is a good idea for a lot of boards - the "Faikin" being one of the few cases where that is not sensible as it fits and existing connector with power. If I move to ESP32-S3 for example, I'll see if that can do USB sensibly directly, but I want a module like the ESP32-PICO-MINI-02 really - not sure if there is one yet.

Oh, and as you may notice, I have adopted a policy of GPIO numbers on silkscreen - it really is damn useful when you have so many generations of so many PCBs lying around. I don't do a lot of silk screen - i.e. no R1, R2, etc, but I have to do some to stop JLCPCB asking questions about pin 1. But GPIOs is invaluable. And now KiCad allows proper fonts it is slightly more fun (the above has "faikin.revk.uk" in xkcd script, err, because I can).

Update: As suggested (and as per above image) I have now gone for staggered pins, to see how that goes.

Update: The silk screen does not work that small, so going for something simpler...

Update: I am also, as someone suggested, trying a CH340X which is physically a similar size for the FT231XQ but a lot cheaper and simper to wire up.

Superimposed CH340X (green) on FT231XQ

Design for USB-A ESP32-PICO-MINI-02 with RGB LED and CH340X

Update: Fuck sake, read the data sheet. 4k7 from CTR to DTR/TNOW is needed, not 4k7 from 3V3 to DTR/TNOW. Sadly meant some boards could not even be reworked. But was able to test this for future boards.

Bed sensor

Some time ago I got a Withings sleep sensor. Not cheap. I am not really sure it helps me understand my sleep well. It does a lot - tracks sleep, types of sleep, snoring, sleep apnea, heart rate. Clever bugger.

However, it does not allow you to use it without consenting to your data being used for other things, which, seems to me, to be a clear breach of GDPR. Obviously I reported it, and ICO were obviously inept, though they got as far as referring to EU, and then Brexit happened, so no idea where the case is now. I think it has fallen down the cracks and Withings just ignore GDPR, it seems.

Apart from some interest in what it says about my sleeping, my main use for this is reporting to my home automation when I go to bed and when I get up. I then link this to various things from simple lights, to air-con, directing the vents for lossnay (fresh air), illumination settings on environmental sensors, and so on. I rather like that lying down turns off the lights, and that getting up in the night turns on one light on a mirror in the en-suite bathroom. If I get up in the morning for 5 minutes it turns on the rest of the lights, and my office air-con, and so on. The possibilities are endless and there are people that are way more in to this than I am.

The problem is that the way this works is convoluted!

• Sensor detects in/out of bed.
• Sends to Withings which is in France I think
• That is linked IFTTT - no idea where that is
• IFTTT does a get on my server in my loft
• My server pokes MQTT for various things to happen

It can take a few seconds to a few minutes, or not at all if any servers or internet access is not working.

The solution

Recently I realised that a simple bed sensor mat is something one can buy cheaply. I mean I realise now that obviously such things must exist, but it had not occurred to me before.

I got one of them - a larger one for a bed (amazon, or cheaper direct). They also sell smaller ones. They could be used on a bed, a wheel chair, even under a door mat. They are sold for healthcare to track someone getting out of bed, or falling out of wheelchair, etc.

I was surprised to find it copes with my thick memory foam mattress, and slats. The Withings one has a pump to pump it up with air to adjust for weight of things like a mattress, but it is doing more than just detecting I am on the bed (e.g. heart rate, etc).

Withings (top, grey) and new sensor (bottom, white)

The trick is what they connect to - alarm devices are sold to work with them. I decided to give it a try, and found it was actually easy to make this work with my home automation. The trick was to use a Shelly Plus i4 DC (here). The reason for the DC model is that I don't want mains under my bed really, and the switch inputs on most Shelly are mains. They do an isolator which has digital and analogue inputs which would allow a Shelly Plus 1 to be used, but the DC i4 is easier. The other feature is it can work from 5V to 24V, and so can be powered from a USB socket. I got a USB lead (amazon).

Too many USB devices already!

The wiring was simple - the sensor appears to be a simple passive sensor. The 4 wires are actually two wires connected and two wires connected, so only effectively two wires, between which is open circuit when no pressure. When pressure applied they go to around 2kΩ, but I suspect it changes with the level of pressure. Thankfully it is low enough to trigger the input on the Shelly Plus i4 DC.

The sensor operates like a switch input, and so can be linked in to any home automation that can work with a Shelly. There is HomeKit stuff for that, but I re-flash with tasmota personally. Obviously this could work up to 4 such sensors, ideal for his/her side of bed, or floor mats as well, etc.

The nice thing is that it is instant in reacting, though obviously I can add a delay if I want. The important thing is it is not a random 10 seconds or several minutes delay as before.

Shelly Wall Socket UK

Shelly sell a lot of really cool IoT stuff, and are particularly nice with a consistent re-flashing port allowing their kit to be used with other software (like tasmota) easily. They also support DC working on several devices. I really like their stuff. I have probably close to 100 of them.

Recently I saw on the shelly EU store a number of Shelly Wall Socket models including Shelly Wall Socket UK. So I ordered one to have a play with. It needs a separate faceplate too, and looks like you can get a double faceplate. The cost is €7.20 for the socket and €3.90 for the frame, so around  £11 total.

DO NOT BE FOOLED!

It is just a dumb unswitched power socket. A boring dumb unswitched power socket. An expensive boring dumb unswitched power socket. Note that an unswitched one gang socket is £1.55 from screwfix and I can get in 10 minutes, not 3 weeks.

Their web site does state: There is no relay device included in the package. But that was really not that obvious.

• I have no idea why they would even sell a dumb power socket at 7 times the price of one I can get locally, especially as they don't sell anything else dumb that I know of. They sell smart IoT stuff.
• It does not even state BS1363, but is CE marked (not UKCA, but was sold in EU shop, but presumably for a UK market?)
• The faceplate does not seem to have any clean way to remove it once installed. There is a slot to get a screwdriver in, but that does not lead to the clips, you would have to force it off. Messy.
• The screw fixings look the right spacing but slotted not just holes so not how you would normally fit to a UK back box, and unlike the £1.55 faceplate, it does not come with any screws!
• The faceplate outline is smaller than a UK one gang socket, so even if it fits it will look odd if used with a back box as the back box surround shows and looks messy.
• As you can see from the picture above, the package has the text "Alterco Robotics EOOD declares that the radio equipment type Wall Socket UK..."

They could have been clever, they could have made a socket that takes (or comes with), say, a Shelly Plus 1PM that clips in the back. The L/N could be tags that go in to the Shelly Plus 1PM even. The Shelly Plus 1 PM has a small mechanical button on it, and they could have made a button on the front press that even so it would work as a switch. So many ways they could have made this consistent with Shelly product line, but no.

Overall I feel selling these at all is actually damaging to their reputation, especially as people will assume it is "smart" and no amount of warning on the order page will be obvious when included with a whole list of other "smart" devices.

PS, I stand corrected, they do sell a Shelly Mug that is clearly not smart. They made a mug out of me.

Shelly Plus i4DC GPIO

As previously posted, I am quite impressed with Shelly stuff anyway, but the new "Plus" range has allowed some interesting developments - as they use ESP32, which is the processor I use for my access and alarm system.

This has meant I am able to add bits to the alarm system much more simply than using my custom boards - anywhere. As I reported before the Shelly Plus 1 is great as it can work on DC or AC, but this modules is specifically for DC usage.

The Shelly Plus i4DC, which is like the Shelly Plus i4 (which is AC), is powered from 5V to 24V DC. This is great news as it can work from 12V and 24V alarm systems, and the typical 13.8V of a battery box quite safely. You could even wire to a USB 5V supply.

It has 4 inputs which connect to GND, and this works well for connecting to fire alarms, door sensors, and so on, and can easily have spares for tamper and dummy wires. I would struggle to make something like this for the same cost, and when I factor in my time this is a total no brainer.

I have also worked out the GPIO:-

• GPIO0: Output for small LED (hard to see through case).
• GPIO12: Input for SW1 signal (external switch) but needs configuring as pull down.
• GPIO14: Input for SW2 signal (external switch) but needs configuring as pull down.
• GPIO27: Input for SW3 signal (external switch) but needs configuring as pull down.
• GPIO26: Input for SW4 signal (external switch) but needs configuring as pull down.
• GPIO25: Input for small yellow button on the case, but needs configuring as pull up.

There are also 6 external connection pins for programming which are common to most Shelly, and not mains live on this model:

• GND
• GPIO0
• EN
• 3V3
• GPIO3 RX to shelly
• GPIO1 TX from shelly
• GPIO16

These can easily be flashed with tasmota too, use the ESP32 solo build. Note I cover two extra GPIO than the usual tasmota config (GPIO0, GPIO25).

Shelly Plus 1 GPIO

I am quite impressed with Shelly stuff anyway, but the new "Plus" range has allowed some interesting developments - as they use ESP32, which is the processor I use for my access and alarm system.

This has meant I am able to add bits to the alarm system much more simply than using my custom boards - anywhere I need just an input and/or just an output, for £15.99 I have a device that does the job. As an output it is a dry contact relay, and can be powered from 12V DC, or 24V-240V DC, or 110V-240V AC, so very flexible. Working with alarm system 12V DC or 24V DC is easy. Only catch is it should be 12V not 13.8V so a regulator may be handle, but it seems to cope without, so far.

The input is run at "live" so for mains working needs a proper switch rated for mains such as a light switch (or one of the nice retractive switches). But working on alarm system 12V, a simple contact like a reed switch, or connection to a PIR is simple.

Obviously there are plenty of uses for the alarm system that needs more than one input or one output, but this is pretty useful. I even have one electrically locked door that is just using one for the lock and door open inputs as it is a door that does not need a fob, just needs to be locked when alarm armed, and detect door open as an alarm input ("access", causing alarm if armed).

My new EL560 locks on the house are great as no need for break glass or exit button as they open with the inside handle. But if you have any doors you keep unlocked during the day, you need a way to lock the doors at night. And that needs a button. Well, a Shelly Plus 1 is ideal. The light shows the doors have been locked.

I have also worked out the GPIO:-

• GPIO0: Output for small LED (hard to see through case).
• GPIO4: Input for SW signal (external switch) but needs configuring as pull down.
• GPIO25: Input for small blue button on the case, but needs configuring as pull up.
• GPIO26: Output to work relay.

There are also 6 external connection pins for programming (WARNING: THESE CAN BE LIVE):

• GND
• GPIO0
• EN
• 3V3
• GPIO3 RX to shelly
• GPIO1 TX from shelly
• GPIO16

These can easily be flashed with tasmota too, use the ESP32 solo build. Note I cover two extra GPIO than the usual tasmota config (GPIO0, GPIO25).

UK smart light switches

Obviously I have tinkered with smart light switches, and the like, for a long time.

You only have to look on Amazon to see a lot of different options now, but there was one simple combination that has been lacking. I have been looking for this for ages, and finally they now exists - the Shelly 1. But more on that at the end of this blog post. First a bit of background.

UK lighting circuits

One of the problems is UK lighting circuits have a live and switched live to the light switch from the light fitting. This means that, at the light switch, there is no neutral. The only way to power a "smart switch" is through the light bulb, which is not ideal. Indeed, it is not that reliable as it also depends a lot on the type of light bulb in use. This means that almost all smart light switches need the wiring changed to allow live and neutral to the light switch. In simple partition walls that is not too hard for an electrician to pull through a new cable, but it is not always so easy. The other big issue is that you almost always have to change the back box from a shallow back box to a deep one, and that can mean chiselling out some brick, etc.

Basically, fitting a smart light switch in the UK is a pain, needs an electrician to do properly (and I am not even trying to address the regulatory issues here), and costs a lot more than just the switch itself.

There are now, finally, some UK variety smart switches, e.g. DS-102L. It has a bypass capacitor to fit across the light bulb so as to allow enough in-line power for the switch. This again is fiddly for a non technical person, but saves running new wiring. I am making the huge assumption that this is valid wiring in the UK as well.

Some options

There are a few approaches to smart lights though...

• A smart switch. But as mentioned, in the UK, this is not always easy.
• A smart bulb. Simple, but tends to cost more (I'll not go in to these here, but Shelly do one!).
• A smart in-line power relay in the lighting circuit.

Yet more problems

The other problem is how you control your smart light switch. Obviously some sort of app on your phone, or integration with Alexa or Siri or something. But then what?

We tried - we really did. I got a simple smart light switch, and we decided to try and get it working as intended. I have used these for years, but always re-flashed with new firmware, so trying it as sold was new for me. A (non technical) relative wanted to simply be able to work some lights, from her phone, remotely, so this seemed like a good idea. I also asked my son to try, as a new pair of eyes. No joy!

We even set up a bog standard router with NAT and WiFi (yes, NAT is evil), and still could not get the damn thing to work as intended. They come with an app, which was easy to download, but then we could not get anything to actually work. This did surprise me, to be honest.

We ended up putting a raspberry pi running MQTT (mosquitto) and a tasmota flashed in-line power plug for a lamp.

Using the Internet

The other concern I have is that these things normally use servers somewhere in the Cloud, i.e.on the Internet. No idea where. No contract in place with whoever runs the servers. No recourse if they stop working. No idea if usage patterns are logged or sold somehow. And all this relying on working Internet.

Call me old fashioned, but I like a light switch that does not rely on working Internet and someone else's server in China!

Of course this means having my own "hub" of some sort - in my case a raspberry pi and MQTT server, but this could be some "home hub" or some such.

Tasmota

If you have not encountered Tasmota before, do take a look. It is free open source software that runs on most of these smart switches and devices. It means re-flashing the device, and they vary in complexity from "having a header you can just plug in to with a serial lead", to "soldering bits of wire inside the switch". But once re-flashed they can be re-configured and re-programmed over the air (WiFi). As for actually flashing the code - you just need a simple serial lead and the tasmotizer app, and it is very easy.

The key thing about Tasmota is that it works using a simple standard called MQTT. Having an MQTT server in your home is cheap and easy, and can integrate with various home automation systems. It does not, then, rely on any Internet connection or third party servers. It can work with various home hub / automation systems as well.

Some options

The main three options I would consider are these. All can be flashed with Tasmota.

• Sonoff basic: This is a neat, very cheap, in-line, 10A switch. It has live/neutral one end, and switched live / neutral the other. It has a tiny button and LED as well, which are not that useful. The main downside I have found is they have a tendency to die after a while.
  
  
  
• DS-102 light switch: There are a lot of these type of smart light switches. The key thing with this particular model is that it has actual tactile micro switches behind the buttons. There are many that are capacitive, so harder to work in the dark when not looking. Some also have LEDs you cannot control. But the DS-102 seems about the best I have found so far. They come in one, two, and three gang, and as mentioned they have an option for live only, supplied with a capacitor to fit across the light fitting. One big down side is you have to solder wires to re-flash them (though people have made rigs with pogo-pins to do this).
  
  
  
• Shelly 1 relay: This is what I have been waiting for! It is a relay, like the sonoff basic. It costs more than the sonoff basic, but typically less than one of the smart light switches. See below.
  
  
  

The Shelly 1

I have been after this for a long time - I even considered making one myself - something simple like the Sonoff Basic, but with a proper switch input. The Shelly 1 seems to be ideal for light controls in the UK.

It can go behind the light fitting in the ceiling where the live and neutral are already present, so solving the fact we don't have neutral at our light switches. But it can take the switched live as an input. Obviously it can have a default mode of operation where the switch works the light, so even no Internet or WiFi does not stop it working in the obvious way.

It has a simple header for re-flashing (please do take note of the warnings about these being at live voltages when connected to power!). So loading Tasmota is a doddle.

This means that with no extra wiring, and no changing to a deep back box, and no change of light switch to something cheap and tacky white plastic. It is easy to make a normal light fitting WiFi connected.

It is also 16A not 10A, so much more useful than the Sonoff basic (obviously for things other than lights, which get nowhere near that rating).

I have one coming today :-)

P.S. For those that have not used tasmota, you can have an input as a button or a switch. A button works toggling an output on pressing the button. A switch toggles the output on change of input. So a normal light switch would be connected in switch mode, and turn on/off when changed. If you override via MQTT you simply swap the way it works, much like a normal two-way light switch arrangement, so the switch now works in reverse until you next override.

P.P.S. Smaller than I expected - this is really neat, and can even run off 12V or 24V-60V if you need. This is exactly what I wanted!

P.P.P.S. I had not heard of Shelly before, but they have loads of cool stuff, all looks quite sane, including the simple to re-flash header, and the fact they will do MQTT anyway. Very cool. shellystore.co.uk

(Do always follow local electrical safety regulations, please)