Teleinfo with Wifi on the Linky

Following the upgrade of my electricity meter (from rotating disk to latest generation of smart meter), I am now able to use the Teleinformation output (hurrah!)

Linky

The Linky smart meter has a slot for a "LRT" module and a 3-pin header for teleinfo (the traditionals "I1" & "I2" as well as a power source named "A").

There are also two communication modes available: Historical (the only one available so far) & Standard (i.e. the new one starting with Linky).

LRT

The "Linky Radio Transmitter" (Emetteur Radio Linky) is a module developed to transmit the value to a household display. Specifications show they can be using either Zigbee or KNX. It was supposed to be totally open but I am yet to see a schematics of it.

At least the Interface Specification is available. I reused the name of Zigbee attributes for the MQTT publication.

Teleinfo

Official docs are available (in french) on Enedis's website, in particular NOI-CPT_02E for Teleinfo in general and NOI-CPT_54E for Linky in particular.

The electronics part is mainly based on work done a long time ago by others, specially Charles Hallard (Démystifier le décodage Téléinformation et l’optocoupleur SFH620 and PiTInfo V1.2, en finir avec la téléinfo capricieuse).

Board

My board is vague cousin of Charles Hallard's Wifinfo but where most of the components are already embedded on the nodemcu module.

CH340G (USB to UART)

Something worth noting is that CH340G seems to be struggling with 7N1 (7 bits instead of the usual 8). Although it doesn't matter for day to day usage of the ESP8266, it makes tests (emulation of the Teleinfo frames) more difficult.

It could be the driver though I am using Linux. Using boards (Amica) based on CP2102 or FT232 didn't show any problem.

Power

From the meter

In theory, the pins "A" and "I1" are maint to be used as the power source. That said, the characteristics are 6 Vrms (50 kHz) and 130mW. This is far from the ESP8266 requirements (~ 150mA) and if it would be easy to rectify and smooth the current, a storage system (super cap or battery) would be needed to deliver peaks of currents every time the data is published (re-charging being one while module is in deepsleep).

External 5V source

To keep things simple and since I already had a 5V source at my disposal, I used the embeded regulator on the nodemcu board (through the Vcc pin but it could have been through the micro-USB socket).

OTA

Having the circuit permanently plugged to the meter means that the option of remote updates is a big bonus. The module is off/asleep most of the time so the best method was the HTTP Server one. But in order to make things easier and more secure, there is a physical jumper to allow OTA or not. When jumper is on open position, no OTA is possible. In the other position (closed), every time the program starts (i.e. every minute), it checks if an upgrade is available.

This is were the additional python script comes handy. By running a webserver and comparing the MD5 checksum of the firmware on the module to the one on the server, it is possible to launch the upgrade sequence only when necessary.

MQTT

Selected data is transferred using the MQTT protocol. As mentioned above, the names/topics used are based of the ones in the ERL/LRT documentation.

ADCO  --> Serial Number used in topics (ssssssssssss)

BASE  ---->  cm/teleinfo-ssssssssssss/data/index {"value": "000073370"}
PAPP  ---->  cm/teleinfo-ssssssssssss/data/apparent_power {"value": "00320"}
IINST ---->  cm/teleinfo-ssssssssssss/data/rms_current {"value": "001"}

Since the tariff is a constant one and not a differential one, there is only one reading to report and there is no need to advertise which tariff is active. People dealing with Heures Pleines / Heures Creuses would have to change the code.

Deep sleep

In order to reduce the amount of power drained, reduce the heat production and because there was no need to keep the module on for nothing, I decided to turn the wifi off. But it turned out that it isn't as straightforward as it initially sounded. Just calling the corresponding fonctions doesn't really make any difference in term of power consumption and forums are full of examples looking really like black art.

On second thought, I decided to go to the deep sleep route which turned out to be easier to implement and perfectly adapted to this kind of usage. The teleinfo is continuous with values coming all the time but having a refresh every second or so has very limited interest. Even everything minute is kind of luxury.

The only downsides of deep sleep are the need of a physical wiring for reset purpose and that the programme really resets every time. In this case where the bridging is stateless (state/info is held by the smart meter and given every single time) it doesn't matter the least.

Next version

This version has been running for a while without any issue. Once the meter is properly registered by the supplier (they seem to have technical issues actually), they should be able to change the mode to "Standard".

This new mode is only in Linkys, uses a different serial speed (9600N7 instead of 1200N7) and provides more information. The "codes" are slightly different too.

There is no physical modification needed and everything is documented so making the software changes should not be too complicated.

Will see....

Code

As usual the code and schematics are available (AS IS) on github.

CO2/Humidity/Temperature Sensor

This project is a mashup of different experimentations. I wanted to try the SHT21 sensors and I was looking for a CO₂ sensor at the same time accurate and not too expensive.

CO₂ Sensor

Until recently, gaz sensors were either analogue (and totally uncalibrated) or relatively expensive (when not both at the same time). Then came the MH-Z14 which is a affordable "Non-Dispersive InfraRed" sensor, in theory quite selective.

The MH-Z19 from the same company can be found for ~ $25. The main issue is the partial documentation. Some commands are still a bit obscure.

A great source of information is the wiki https://revspace.nl/MHZ19 and there a quite a few examples on github to get started.

At first experimentations were a bit frustrating but after a while things started to stabilise a bit and sensor's readings from the past few month seem to make sense. The solution was to reject sub-standard readings and to average valid ones over a period of 5 minutes.

One quite annoying thing a bit this module when using breadboard or prototype PCB is that it has weird dimensions (not a multiple of 2.54mm) and won't fit nicely.

Calibration

Calibration can also be an issue, specially because of the ABC calibration every 24h. The system would be great if it spanned over let's say a week which would give you several chances to open the window but as it is (i.e. using the minimum value of previous day as base), reading were becoming strange day after day. It turns out that it works a lot better without ABC and a manual calibration from time to time.

Then manual calibration can be triggered by software or using the hardware pin. To avoid trying to fit a switch on the enclosure, the solution retained was to use a reed switch inside and to press a neodymium magnet on the cover once the air of the room has been well recycled.

Wemos D1 mini

Although I initially planned to use nodemcu modules, I decided to try Wemos D1 mini which are smaller, cheaper and able to cope with higher speed communication via USB so firmware upload is twice as fast.

Besides this, there really behave like any other ESP8266 solution. Wemos offers a good selection of shields (power, relay, LED, sensor, ...) which I haven't tried as well as modules based on the more powerful ESP32.

It is probably best to use their official online shop as there seems to be quite a lot of fake modules around, and not necessarily cheaper.

I2C Oled

Having used a 0.96" Oled screen for the time bomb, I really thought that using a 0.91" 128x32 I²C SSD1306 screen would be trivial. As it turns out, library for the former is not compatible with the latter because they lack of a proper framebuffer. After digging around, I found that the Adafruit library was working (one parameter is of a different value) even if the hardware looks quite different (more pins).

To be perfectly honest, if I was to make another sensor, I would give up the screen and use coloured Led shinning through (the plastic is slightly translucent) as the physical fitting was probably the most challenging part of this project (even if simple by DIY standard).

A sprinkle of MQTT

Communication with base is, of course, via MQTT, nothing new or complicated here. There is a sampling every minute for the CO₂. The average value as well as the current values of temperature and relative humidity are sent every 5 minutes.

Wifi off (really?)

Since this new sensor is installed in our bedroom, I wanted to switch the Wifi on only when needed MQTT communication to send the values. I basically used the dedicated function for this. Is is really switching off "radiations"? Who knows... as I discovered with the electricity meter project, electric consumption is not lowered by it.

Powering the sensor

I knew from the start that using battery would be a challenge and I didn't even bother. Between the screen, MH-Z19 and the Wifi, it is probably around 200mA anyway. The USB port of the Wemos D1 mini is plugged directly on a small power adapter. The usb cable can also be used to upgrade the firmware as no OTA was implemented on this project.

All in a "sensor box"

Like almost everything else, directly from China, I found an enclosure designed for sensors (or thermostat?) which was the right size to fit everything. The USB power adapter is external, the ESP8266 at the top and the thermometer at the bottom, by the vents in order to stay as accurate as possible. Despite this, the temperature appears 1.5°C higher than without cover. The offset can be corrected in software.

Code

As usual the code and schematics are available (AS IS) on github. It includes a SHT library and MH-Z19 library.

New meters

Back after a hiatus of a few months. The main reason can easily be guessed from the previous post! :-)

This time I will be talking about so-called "Smart meters" since both my antiquated electricity meter and gas meter were recently replaced.

Linky

Linky is the name for the French electricity smart meter. They are manufactured by different companies but all have exactly the same flashy green colour!

Linky is highly controversial but not for the right reasons IMHO. Opponents seem to concentrate on false and bizarre statements about radiations when they don't assert the meter embarks a camera! Long term loss of job (meter reading people) and above all the risk of privacy breach (it is technically possible to know how much electricity is used in real time hence to know what are people's daily routine and/or if they are on holiday, etc...) could have been causes worth a battle. But honestly opponents only managed to discredit themselves and look like a bunch of lunatics!

Let's not forget that the original reason behind the arrival of smart meters is (by extension with smart grids) to be able to better handle the production of electricity by "green" means (wind, solar, ...) which are highly unpredictable and require to collect real time usage to try to balance production and consumption.

The fact you can now be charged with real amount rather than estimates and you don't have to be home any more to open the door is a real bonus too. Note that in France, contrary to some countries like the UK, you don't have a "smart energy monitor" in standard. This kind of display with the current consumption in currency seems to be given only to the poorest families. AFAIK there isn't any similar solution sold yet.

There is a slot for the emitter module ("ERL") and "Teleinfo" is available! Hurrah!

So my first task was to create a MQTT/Wifi module to transmit the real time data. I'll give all the information about it soon.

• All about Linky (in French) - Canard PC Hardware
• All about Linky (in French) - Canard PC Hardware - Pdf
• G3-PLC, the standard of the LINKY roll-out and beyond - Pdf

Gazpar

The smart gas meter is called Gazpar and is controversial too (obviously!). The transmission of information is slightly different. First it is only one-way and for reading: Nothing can be done remotely. Reading are transmitted by FM then mobile network twice a day.

It is like a old "dumb" meter clad in an bright orange cuirass.

For me the main issue is the loss of the magnetic pulse reading. I actually suspect that is is used internally by the Gazpar electronics but it is no longer available for personal use.

There is a "socket" but I can't find much information about how to use it (dry contact? Not so sure specially that the battery should last 20 years and in theory the fact that something is plugged in is sent to gas provider) and I am rather shy to try anything. If someone has any information about it... Please contact me.

The good news is that there is a shiny "6" on the litre digit so, reusing the old electricity light sensor, I am able to count the "pulses".

• Le compteur communicant gaz - GRDF - Pdf

Le compteur gazpar est équipé d'une prise. Cependant quasiment aucune information à ce sujet n'est disponible. Cela pourrait être un contact sec mais j'ai du mal à croire qu'il s'agisse d'un relais (avec une pile qui doit durer 20 ans et du fait que l'utilisation/occupation de la prise semble faire partie des informations remontées). Je suis preneur de toute information à ce sujet... Merci d'avance.

EDIT (16/12/2018):

The cable is for sale on (at least) two online shops. By the time you add VAT and postage, it's almost 20€ or 24€ (horrendous for what it is) but let's hope the price will go down with time.

Regarding how it is connected internally, I still haven't been able to find any documents but my best guess is that there are 2 reed switches bundled together, one used for the internal counter, the other one directly connected to the socket.