Build your own CT Clamp Power and Energy Monitor with ESPHome 

Not a problem

Thank you!

Create a helper of the type 'Integration - Reimann Sum Integral' and use your power sensor as the source. That will give you a cumulative energy sensor. Once that starts to build up with data, you can then create more helpers of the type 'Utility Meter' using the new energy sensor as the source, and they can be on a daily/weekly/monthly cycle as required. I use a daily cycled utility meter sensor in my energy dashboard which gives you loads of graphs!

Thanks 👍

The same company (Mottram Labs) which supplies the Mains Power Sensor board also sell a 4-channel Mains Power Sensor board. Same principle as in my video, only there's four 3.5mm jacks for CT clamps. This could be a good option. If you'd prefer something more off-the-shelf then you might want to look at the Shelly 3EM which can monitor three live cables simultaneously. As for creating your own smart plugs, I can't advise on doing that for safety reasons. I personally prefer to use either Z-wave or Zigbee power-monitoring smart plugs (such as these zigbee ones: amzn.to/3VqSeQE), or you can go for one of the many WiFi smart plugs that offer power monitoring too from Amazon for under £10 each. I think you'd struggle to make them yourself for that small amount anyway!

Don’t forget that these clamps can only detect uni-directional current. They don’t know if you’re importing or exporting. As for configuring the multi socket modules, there was already a great article on the web showing you how to use the multiplexed signals (ryanteck.uk) but that site is down right now :( You need to configure an ADS1115 sensor instead of an ADC sensor, and then each clamp is a separate multiplex on the ADS1115 bus.

Did you figure it out? I am also doing a 20 CT clamp project.

@@olahe97 i got it sort of working but ran out of time and so i bought an emporia. I managed to get it linked up to HA but could only get one Chanel to work properly. All 4 channels read the same as channel 1. im going to re visit it next week to try and get it working, ill let you know how i get on.

The blueprint is on the seller's web site (www.mottramlabs.com) so there's nothing to stop you buying the components and making up your own on a breadboard. It won't be as polished and requires a bit of soldering, but it's not impossible.

If you are using this on your grid feed and there's a chance you could be exporting then you may want to look at a different product. This solution can't tell which direction the current is travelling. As for battery powering, the code was written on the assumption it would be powered by a mains supply. In order to save battery power then it would need tweaking to measure less often and sleep in between. You could probably reduce its overall power consumption to 25% as a rough guess by optimising it that way.

Thank you, that's very kind of you! I'll let you know if any interesting projects require 3D printing :) There are none planned right now but I'm sure I'll think of something.

These only measure current. You need a different type of sensor to measure voltage.

Hi - the link to the code I used is on my web site (www.speaktothegeek.co.uk/2022/08/esphome-ct-clamp-power-and-energy-monitor/). I assume you already have ESPHome installed in Home Assistant? If not, that's your first step. Depending on how you are running Home Assistant, you either install it as an add-on in the add-on store (easiest way if you are using the 'supervised' version of Home Assistant), or you'll need to manually spin up a container somewhere to run it. To program the device, you create a new device in ESPHome (any settings will do to start with), then edit the configuration manually and paste mine over. You'll need to have set up some secrets (see the items prefixed with !) in the Secrets page of ESPHome for things like Wifi passwords / other passwords. You can then plug your microcontroller into your laptop using a microUSB cable. Use Chrome (or you may get issues), and you should be able to use the 'install' option in ESPHome to connect directly to the locally connected microcontroller. How to use ESPHome is probably worthy of a video in itself and there are plenty of starter guides out there. I might do one myself soon...

@@SpeakToTheGeekTech thanks so much for the detailed response. Doh, I’ve scrolled through so many pages of documentation over the past few days, I totally missed the code, sorry! The 3 x D1 minis I ordered via the amazon link came today, they don’t have the headers soldered on but I’ve got a soldering iron and it adds a bit of fun to the project. In terms of calibration, I have an idea to use a hand held current clamp meter. I know some use things like a kettle, but my logic is measuring the mains feed I actually want to monitor should give me a more accurate calibration? Thanks again, I’ll let you know how I get on!

Sure - you need to create an 'integration' helper from the power sensor. Settings > Devices & Services > Helpers. Click the create helper button, "Integration - Riemann sum integral", choose the CT clamp power entity as the input sensor. You can then use that sensor in the energy dashboard, but I suggest you then create another helper of type "Utility Meter" and use the new Integration sensor as the source entity. You can then set the Meter Reset Cycle to one day, and use that utility meter in your energy dashboard.

@@SpeakToTheGeekTech OK I'll give that a try. Thanks so much for the reply

It calibrates the sensor and device rather than the item it’s connected to. Keep in mind it only senses import current and is only ballpark accurate. Useful for knowing if there’s nothing / little bit / loads of power for the average curious Home automationist, just don’t rely on it to compare against your bills.

You're probably right. There is no ESP32-friendly version of this add-on board though so it would make the project trickier and less neat for beginners certainly. There is a 4-channel version of the ESP8266 board with an external ADC (ebay.us/wE7aJZ) which would be more accurate, and looking at the Mottramlabs web site there's a 4-channel ESP32 board 'coming soon' now too!

You REALLY need to explain why you feel the ESP32 ADC is 'crap', as you so quaintly put it, and in what context. Is it noise, resolution, LSB uncertainty, drift? It doesn't help anyone just saying it's 'crap', some shortcomings, after all, are irrelevant depending on context?

@icarossavvides2641 Well, the ADC on the ESP8266 is about as good as your reading and comprehension skills.

To my knowledge this only works with AC but you’d be best off contacting the seller to find out details like that

Calibration didn't work for me. The amps just didn't show up. I've ordered a more up to date Mottram board off ebay to see if I can get it going.

Do you have the CT clamp around just a single core (live) cable, or around a flex (triple core) cable? If there's a live and neutral running through the same cable that you have the clamp around then no current will be shown (the neutral cancels out the live).

@@SpeakToTheGeekTech I'll look into this. Thanks so much.

@@SpeakToTheGeekTech I am learning a lot while I do this... I have been frustrated that my CT sensor hasn't been reading anything when it should! It turns out that my 50ma current sensor (like yours) was actually the other model that works on voltage and had been labelled incorrectly from the manufacturer!

Mottram Labs also sell a 4 channel version of the current sensor module, but if I were looking to monitor a larger number of circuits then I'd probably go for a Shelly EM (or 3EM) instead. I would suggest that this build-your-own method is for 'casual' monitoring.

@@SpeakToTheGeekTech Thanks, just to follow on from this, the Shelly EM only does 2 circuits (there's a 4 but overkill and limited total amps). Mottram Labs does 2 versions, one which uses the ESP8266's own A/D for measurement, the other has an onboard ADS1115 A/D converter is provided for the measurement (15 bit), any preference (like which would/might be easier)? A 4 circuit version could work if you're only looking to track the biggies- say heat pump, solar, car harger- and (time)-manage the loads, I personally wouldn't be looking to track every light bulb.

I've not actually tried the one with a onboard A/D converter yet. When I get chance I will order one and give it a go. I'm interested to see the difference, but it's just one of those things I've not got around to yet.

@@chrishorn1032 I would like to monitor every single appliance but will likely settle for each breaker. thanks for the feedback

The easiest way is to just edit the sensor in Home Assistant and change the units there, but you could do it in ESPHome instead and divide the output sensor value by 1000 before sending

Im trying the work out how much its costing me to run my heat pump, is there away I can show this data in kWh?@@SpeakToTheGeekTech

@@jamesabbott9606 Yes, create a new helper of type 'Integration - Riemann sum integral' and use the power sensor as the source.

That's brilliant! thanks, Ive used your other video on off peak tariffs, so I can work out my heat pump cost either off peak or peak! Ive also ordered the glow CAD, so im watching your video on how to set that up@@SpeakToTheGeekTech

Hi, there could be several reasons for that message but the most common ones I've come across are either a dodgy micro-USB cable, a missing serial driver on your computer, or an incompatible web browser. On a Mac, you used to have to install a serial driver but it's now included, I don't use Windows but there is a serial driver available for it on their web site (www.wemos.cc/en/latest/d1/d1_mini.html). Use Chrome (not Safari or Firefox) as that makes a difference too. You could also try compiling the file locally on your Home Assistant installation, downloading it, then using the ESPHome Web Tool to push it to your D1 mini (web.esphome.io). Hopefully at least one of those suggestions will help you out.

@@SpeakToTheGeekTech Thanks very much for the reply, but the problem was me being an idiot! I was connecting the D1 to the laptop I was connecting to HA with, rather than connecting it to the Thin Client PC that has HA installed on it (doh). It wouldn't compile at first but when I connected the two boards together it went through successfully with your yaml script. So, once again thanks for all the videos and please keep us informed about anything you learn about controlling Solar Edge kit. The reason I went for the expensive SE option was that I thought I could control everything with HA but it appears not. We will see....

There certainly is. You need to turn the power sensor into an energy sensor first by going to Settings > Devices & Services > Helpers, clicking the Create Helper button, choose Integration - Riemann sum integral, and choose the CT clamp power sensor as the input. Then you need to create a Utility Meter helper sensor (similar way to the Integration sensor), using the new Integration Energy sensor as the input. You can configure the meter reset cycle to be daily, monthly, yearly, etc... You can also then use a daily utility meter sensor in the Energy Dashboard if you like, and the Energy Dashboard can calculate the cost for you too.

@@SpeakToTheGeekTech excellent thanks so much!

Exposing the cores individually and putting the CT around one of them is the only way to monitor it. Of course that’s not particularly safe in some circumstances so I’d suggest doing that inside a protective casing or wiring box.

Yeah maybe, but they take up space and power and for the three time perhaps that I could have made use of one so far I think it would have been a waste. Still maybe I’ll change my mind!

It's not my PCB design

No, sorry, they're no good for that, just uni-directional flows.

The ESPHome config requires you to either pass it an entity from Home Assistant with your home’s voltage in (line 5) or hard code a value of say 240 on line 59 instead of where it says “id(grid_voltage).state”. If you are hard coding a value, also delete lines 42-47. My SolarEdge inverter is connected to Home Assistant using the SolarEdge Modbus integration. I use the voltage sensor from this integration in my ESPHome CT Clamp configuration. Have a look at this article to see how I’ve done that: www.speaktothegeek.co.uk/2022/05/solaredge-hd-wave-se3680h-and-home-assistant-local-integration/ To get that working, you’ll need HACS installed in Home Assistant and I have a video on how to do that here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-jzpm89956Pw.html MyEnergi is via the integration also available in HACS, and I have an article all about the Eddi. If you have another MyEnergi product, it’s the same process - just scroll down to the section about Home Assistant: www.speaktothegeek.co.uk/2022/10/myenergi-eddi-and-home-assistant/

This particular implementation will only ever show a positive power value so you wouldn't be able to tell whether you are importing or exporting using it. When I get chance I'll take another look at the raw data and see if there's any way of updating the configuration to output that properly.

@@SpeakToTheGeekTech A great video and just what I was looking for to monitor my solar power export to the grid to help size a home battery. But that will need me to be able to record both positive and negative currents. Have there been any developments since your reply to Tony, and would it be possible to work around by having two sensors on the same cable: one to measure import and one to measure export? Many thanks.

I've done a bit of reading on the subject and from what I now understand in order to work out the direction of the current you need to monitor the AC phase, and that would have to be done in realtime by another physical sensor attached to the microcontroller... which doesn't exist on this particular break-out board. By this logic, that must mean that only mains connected power monitors are able to detect direction. Honestly, I'm still not entirely sure what sort of component is required in order to do this, but I haven't given up yet. If I ever figure it out though you can guarantee it'll appear in a video!

@@SpeakToTheGeekTech Many thanks for that helpful reply. I now understand that the CT clamp will only give the magnitude of the current and will not distiguish between directions. However my solar panels have a SMC invertor which gives me regular power readings via bluetooth (average power over 10 minute intervals) to a monitor. I can download the data to my PC. So if I combine this with CT readings, I can split the latter into export and import parts (if(solar>CT, CT = export; if solar

That’s some brilliant logic to get that result. I guess it’s very specific to your setup though but could be adapted for other setups. I have mine monitoring my battery EPS output which can only ever be in one direction due to this limitation, but with some careful thinking like you’ve done I might be able to put it on another feed that’s bidirectional

It's because that's specifically the CT clamp that the board was designed for. To find out if other CT clamps would work you would need to contact the designer/seller of the board. I couldn't tell you the electronic reasons behind that though sorry.

That's a shame. Mottramlabs publish the schematic so if you wanted to get one made using that then you could. A lot of effort though.

@@SpeakToTheGeekTech I'm working on it now

No sorry, it can’t detect direction

There's no auto-detection, you have to specifically configure it in the yaml file. The yaml file on my web site is one I created myself. However some of the 4-channel versions actually use an external ADS1115 multiplexer, so you configure them to talk to the CTs using a multiplexed channel on the ADS1115 (esphome.io/components/sensor/ads1115.html). The ESP32 version of the 4-channel board actually looks like it's using the ESP32's built in A/D with each one connected to its own pin. The schematic here shows which pins are on which channel. www.mottramlabs.com/pdf/SCH201191.pdf

@@SpeakToTheGeekTech Ahh that makes much more sense, I’ll crack on with giving it a good go! Thank you so much for the pointers!

@@SpeakToTheGeekTechUpdate: got it all up and running! Although readings are unbelievably erratic so definitely some more issues to solve.

The short answer is no! But I have dabbled with ESP devices before ESPHome came along and the long route is to use the Arduino IDE, import the external libraries you might need (which will be lots!), and program the board manually using C++. I like ESPHome because it removes the need for most of that and you can just get on with configuring the board with exactly what you want to achieve rather than having to work out which libraries need importing. You can use ESPHome to to what you require too. You enable the MQTT client option (esphome.io/components/mqtt.html) and disable the Home Assistant API. However, I'd argue if you're using ESPHome to do that, you already have Home Assistant, so why not just run your own MQTT server locally on that. I guess it's all down to your own preferences but using native Arduino IDE has a much steeper learning curve.

@@SpeakToTheGeekTech thank you for responding so quickly. I didn’t realise I could use Home Assistant to host an MQTT server, so long as my computer doesn’t need to stay on 24/7, that would be perfect for my needs. Already used your links and bought 5 sets of everything in case I make a mess of the first couple attempts.

No sorry, it doesn't understand directional current

I'm sure I mention in the video that you can either hard code a value for the average expected voltage, or provide the configuration with a Home Assistant entity that is tracking the voltage for you. I use a 'grid voltage' entity provided by my solar inverter. The energy monitor project is only intended to be roughly accurate and isn't a high accuracy component. For that you would need something hard wired inline to do this properly. For hobbyists who just want to know if there's roughly nothing, 100w, or 2.5kW going through the wire, it's ideal and cheap to make.

@@SpeakToTheGeekTech thanks for the quick reply. You did mention it in the video that you can get it from that variable or hard code a value in there. I just didn't understand how that variable voltage info was getting populated. I guess for me, I can make another ESP8266 device and plug it into a 240V outlet with PT clamps, and send the voltage info that way.

Yes that is a possible option, but you’re starting to move into the realms of this become more expensive to the point where you may be better off buying a calibrated commercial product rather than these self build ones. Unless you’re doing it for that build!

@@SpeakToTheGeekTech I'm doing it because I don't know of any calibrated commercial wireless products.

Have you seen the Shelly EM products? They are hard-wired to the mains to get the voltage, use a CT clamp for monitoring current, and connect over WiFi.

I'm sorry, there is only one maker and seller of this item and for some reason they have chosen to exclude Germany from their shipping destinations. I'm not sure why as they ship to other EU countries.

@@SpeakToTheGeekTech Shit :( Did they have an email? So probably i can write them or did you have another company for that?

@@SpeakToTheGeekTech Is it probably possible that you buy me some and send it to me? :)

This is powered by a 5v microUSB cable. With some adjustments to the code to reduce how often readings are taken and to put the device to sleep in between readings, it would be possible to run from a battery pack instead. I don't know how we'd go about harvesting energy from the CT clamp, that's a bit beyond my electronics know-how at the moment!

@@SpeakToTheGeekTech thanks for the info.

The PCB has a specific resistor. The sensor output is a current source and puts a current through the resistor that is proportional to the current measured in the cable. The micro ADC measures the voltage drop across the resistor and uses ohms law to calculate the output current.

How do u solve that?

If you look on the ESP8266/32 page (www.mottramlabs.com/esp_products.html) the second device down (Wemos D1 Mini ESP8266 Mains Power Sensor), there is a button named '3D Files': www.mottramlabs.com/files/Wemos_Case_201083.zip or third item down for the none-SMD version: www.thingiverse.com/thing:3169243

@@SpeakToTheGeekTech thank you very much

If you're in the UK and have a smart meter, you can get that information by using Glow. You might be able to get gas energy data for free using their API or from their Glow IHD which is what I use ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-6MiZ2EMajnA.html

There was a project based on esp32 and ai to read hardware digi

There used to be a few sellers on eBay and Amazon that soldered the headers and re-sold at a profit but a quick look at both sites isn't turning up any results at the moment. Even Banggood doesn't seem to be selling them at the moment sorry.

@@SpeakToTheGeekTech I haven’t soldered for years, decades 😀. How easy is it to solder? I am worried about joining the pins together.

I'm not very experienced with soldering either - pretty much just what you see in my videos! I have a fine-tipped soldering iron which is important, and it's quite easy to solder the headers. I use blue-tack to stick the module to a surface and hold the pins in place face-down, then just melt the solder into the gaps between the pins and the board and it usually just sucks the solder straight up into a neat little bump. I'm not saying it always works, and I've melted a few boards and blue-tack in my attempts, but it's not a difficult task really as DIY jobs go!

@@SpeakToTheGeekTech I overlooked one thing. I was going to put this outside in my meter cabinet, but I have no power to plug it in. That is annoying

That’s odd, are you certain you put the values for calibration the right way around?

@@SpeakToTheGeekTech What did you mean? I putted in like i showed... i dont know :/

filters: - calibrate_linear: - 0.00000 -> 0.0 - 0.00042 -> 2.0 Thats what i typed in. In My logs i have exact these 0.00042 when i put i 2.0A in my battery. But something strange is, that i have 5s interval and sometimes also is 0.0000A and than again 0.00042A But with the calibrate, i have everytime 0.0000A :(

I think you’re calibrating with too low current. You should remove all calibrate linear commands, put the clamp in place and see what you get when there’s no current running through it. That’s your calibrate for 0. Then whack the current right up, usually that’ll be 10 amps +. That’ll give you a reading at the top end of your calibration graph. It’ll then interpret the other values (like 2A) linearly. What’s likely happening now is that your zero current and 2A current readings are very close so overlapping.

@@SpeakToTheGeekTech Ok, when i check Raw AC Value, i have 0.000A i think i dont have enaugh decimals there... is there a way to show more decimals?

I didn’t do anything special at all. I plugged it into my Home Assistant server (Raspberry Pi) using microusb and used the ESPHome interface to flash it. No shorting of pins was required.

@@SpeakToTheGeekTech - It's fine thanks, managed to flash it in the end, something on the machine I was using didn't like it, but in other news, I can't get the clamp to read anything, constantly showing as 0w

All I keep getting is this: [15:22:59][D][homeassistant.sensor:024]: 'sensor.shellyplus1pm_441793a76958_switch_0_voltage': Got state 241.70 [15:22:59][D][sensor:093]: 'Grid Voltage Entity from Home Assistant': Sending state 241.70000 with 1 decimals of accuracy [15:23:01][D][ct_clamp:040]: 'Power Sensor Live Power' - Raw AC Value: 0.000A after 188 different samples (940 SPS) [15:23:01][D][sensor:093]: 'Power Sensor Live Power': Sending state 0.00000 W with 0 decimals of accuracy

Do you have the clamp around just a single live core or have you clipped it around a three core wire with neutral in too? Did you get the exact same model number CT clamp in this video?

@@SpeakToTheGeekTech It's clamped around a 3 core cable, I've bought 2, both the same model (SCT-013-000 - 100A/50mA), does it need to be around live only?

Yes the seller has chosen not to deliver to Germany. I don’t know the reasons why sorry.

i want to hook it up to a ps5 (power cable is in utility room) will the other plugs interfere with the reading/calibration?

No, that won't work sorry for a number of reasons. Firstly the clamp is to detect AC current (not DC used in a USB cable), secondly it must be clamped over a single wire - so inside a normal AC three core flex cable, there's a live, neutral and earth - the clamp must be around just the live and not multiple cores.

True, I am in the UK and the supplier is also in the UK. He does supply a schematic for the board so it’s entirely possible for an enterprising person elsewhere in the world to order or make a batch and sell them on

Hi- I haven’t used any stepper motors at all yet, sorry. I do want to try that out but I need to think of a use-case for it first! ESPHome’s web site has a specific section just for the ULN2003 (esphome.io/components/stepper). It looks straightforward to me, but then again these things never go to plan! The control of it by Home Assistant looks very similar to the way you control a servo like the one I used in my WiFi Water Pistol video.

@@SpeakToTheGeekTech will order one from ALiexpress and have it mailed to you so you can try to get it working. Just looking to share the pain I guess. BTW that link you posted is broken and FYI.

I'm pretty sure the seller will ship to the US?

@@SpeakToTheGeekTech shipping costs to the US are pretty high.

Fair enough. I'm pretty sure the seller makes them all by himself in the UK though rather than this being a large business seller so I'd be surprised if you find them for sale anywhere else.

Yup I totally agree. It's measuring the current and the power is just an estimate based on that. This device however is cheap to make, gives a ballpark rough reading suitable for use in home automation solutions, and is non-invasive for those who don't want to connect to mains power. It's also just a fun little project, but if you're after something seriously accurate then of course you must look for an alternative solution.

Yeah but at the time I ordered it, it was the cheapest online service I could find. I compared quite a few. Now though I know a few people with printers so I could avoid that cost.

Haha best comment so far :) Fair point well made! I guess the real point is that other household members would definitely notice a hulking great 3D printer humming away in the house and start asking questions, whereas an Apple Watch can quietly sit on my wrist and usually go unnoticed... I'd also need to consider the cost for how often I'd use one vs printing the occasional item online. Don't get me wrong, if I could get away with purchasing one right now I absolutely would!

@@SpeakToTheGeekTech I get that - I kept a list of things I could make with a 3D printer and when that list got over 30 items I started thinking seriously about it. I sold my wife on it by extolling how the kids could use for school projects, etc... that has yet to happen ;-)

Point taken... but to clarify - that Apple iMac you see is a 2010 model, purchased second hand from someone else, some internal upgrades from me, but sadly retired only a few weeks ago as it's no longer able to keep up. Those two additional monitors are even older, from 2009. I like to keep kit for as long as possible to reduce the tech churn. It took me many years to save up for that solar array and will hopefully break even in about 6 more years so that's a spend worth making. It's all about choosing your purchases carefully to make the best use of limited funds in areas that are important to you. A 3D printer would be a bit of an extravagance given I'm unlikely to use it that often.

Yeah it’ll never be as accurate as a proper inline power sensor of course, but in order to give the average home user an idea of what is flowing through a cable then it’s in the right ballpark.