Smart electricity meter reader
We are considering a reader that plugs into the customer HAN port of a smart electricity meter and sends consumption per tariff, grid feed-in, power per phase and the current high or low tariff to Home Assistant. We do not make it yet, demand decides whether we will.
- Works with Home Assistant
- Open source
- No cloud
We do not make this yet. Whether we build it depends on how many people are interested. Leave your e-mail and we will send a single message when it is ready, then delete the address.
Illustration of use. Photos will follow from the first batch. See the enclosure
What it will look like
3D design of the enclosure, which you can also print yourself. The product is not manufactured yet, the design may change after the first test prints.
What the reader would do
The smart meters Czech distributors are rolling out have a customer HAN port. The meter broadcasts its data there roughly every minute. The reader picks it up and sends it to Home Assistant:
- Consumption per tariff for the Home Assistant energy dashboard.
- Grid feed-in from solar panels.
- Instantaneous power per phase, for example to watch the main breaker.
- The current tariff, so automations can run the water heater or car charging during the low tariff.
It pairs well with Spot: Spot shows the spot price, the reader shows real consumption and the tariff.
How it would work
It uses the same Jádro board as the other Plošná ryba products, with a small head for the HAN port and a cable with an RJ12 plug. ESPHome reads the meter natively. Indicators on the front show the tariff, feed-in and data reception. Everything stays at home in Home Assistant, no cloud and no yearly fees.
Why we ask before we build it
There are several meter types and they do not all behave the same, and we do not know all details for every distributor yet. So we check demand first and use the answers in the form to pick volunteers for prototype testing. If enough people sign up, we start development.
Specifications
| Status | planned, not in production |
|---|---|
| Meter connection | customer HAN port (RS485, RJ12 connector) |
| Would send | consumption per tariff, grid feed-in, power per phase, current tariff |
| On the front | indicators for tariff, feed-in and data reception |
| Power | USB-C 5 V |
| System | Home Assistant and ESPHome, no cloud, no fees |
FAQ
Am I allowed to connect something to the meter?
The HAN port is the customer interface meant for this. ČEZ Distribuce states that using it does not need to be reported. We will verify the rules of EG.D and PREdistribuce before production. The reader sends nothing to the meter, it only reads what the meter broadcasts.
Why not read the blinking LED on the meter?
On new smart meters ČEZ Distribuce switches off the pulse LED and the optical port, only the HAN port stays. It also gives more data: tariffs, feed-in and power per phase.
Does it replace the ripple control (HDO) receiver?
The smart meter also reports which tariff is active and the state of its relays. Home Assistant knows when the low tariff runs without a separate receiver and without scraping the distributor's website.
My meter is in a box by the fence, will it work?
The reader needs power and WiFi coverage. In a box without a socket far from the house this can be a problem, that is why the form asks and why we will test prototypes with volunteers at different locations and meter types before production.
When will it be ready?
There is no date yet. First we make the first batch of our current products. Leave your email and you get one message once we decide.
Docs and source files
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