This article will provide you with a walkthrough on how you can build a water usage meter sensor that integrates with your Home Assistant for under 10 $/EURO, without the need of any soldering or coding skills.
This article will also cover the configuration that’s needed in Home Assistants to translate the ‘pulse’ to liters (or any other non-metric measurement) in Home Assistant. At the end you will have clear insights in how much water you are using per day, hour and week.
Why do you want to measure water usage of your home?
These days it’s all about insights. I measure pretty much all my utilities, including power and city heating. The last missing piece is water usage. Although water in the Netherlands is not really expensive I wanted to get more insights on how much water are we using and is there anyway to save some water. Unfortunately water delivery doesn’t come with a smart meter. There’s just a analog counter. So how do you measure the water usage and make this analog meter smart?
A lot is changed since I wrote multiple articles around ESPhome. One of the mayor things is that ESPhome is now part of HomeAssistant core and it comes with a nice integrated User Interface.
What are ESP32 and ESP2866 nodeMCU boards?
ESP boards are a low cost Wi-Fi chips that have built in flash chips allowing you to build a single chip device capable of connecting to Wi-Fi. newer versions like the ESP32 boards also provide you BLE (Bluetooth low energy) and there’s loads of variety of boards you can use.
With ESP you can easy make smart solutions for HomeAutomation. You can buy them for about 4-9 dollar/euro on AliExpress or for a bit more with faster delivery on Amazon.
In previous article series I provided an overview and step by step instruction how to make you Bellfire fireplace with Mertik Maxitrol controller smart. This project that was presented during the Home Assistant Conference 2020.
In the article series and presentation I focused on the essential controls, basically turning the fireplace on and off. I received number of requests to extend the controls to support increasing and decreasing the fire and also activating the so called center burner.
After doing some research and trial and error I’ve found the combinations for the relays to add these features to your smart fireplace.
Note: The PIN name is translated from the physical D number printed on the ESP to the addressable name used in configurations and programming. E.g. pin D7 is referred to as GPIO13, all mappings can be found in the image in the ESP Intro section.
UPDATE (thanks Petr): “Fortunately ESPHome knows the mapping from the on-board pin numbers to the internal pin numbering, but you need to prefix the pin numbers with D as in the image below in order for this automatic mapping to occur. In general, it is best to just use the D0, D1, … pin numbering to avoid confusion”
We are adding three switches of the platform type GPIO, this means that the switch will 1:1 control the GPIO pins. For every switch we define the GPIO pin that is controlled, and we provide a name and ID.
Flash the firmware Over The Air (OTA)
That’s it, now flash the firmware of the ESP with the updated firmware based on our new configuration. We do not need to use the flasher tool anymore, we can use the Over-The-Air flash feature to flash the chip with the new firmware over the WiFi Connection. It is as easy as clicking the UPLOAD button.
ESPHome will compile the new firmware, send it over to the ESP that will than flash itself. After flashing the ESP will come back online with the new firmware. It does not get much easier!
Control the relay from Home Assistant
Wait till the ESP has been flashed successful and is connected to the WiFi.
Find your device in Home Assistant, noticed that the device now has 3 entities. Click on the device and you’ll see that it has three switches, called IN1, IN2 and IN3.
Press the switches and enjoy the sound of clicking relays. Every switch should control the matching relay.
Create timing to control the fireplace
To control the fireplace I need to match following sequences with the switches:
Ignition, close contacts 1 and 3 simultaneously for 2 seconds
Fire off, clos contact 1,2, and 3 simultaneously for 1 second
We need to control the relays in these sequences with the ESP board. We can do this by extending the ESP configuration. We’ll add an Ignition switch that will execute sequences above when turned on and off.
Open ESP home and click edit on the node to go to the configuration editor.
Add a new Switch (right under IN3) with following configuration.
Serial port: select COM port where the board is connected (there is probably only one option 😊).
Firmware: Browse to the location where you downloaded your compiled firmware and select your firmware.
Click Flash ESP and wait
The ESP will be flashed now, you can follow the progress in the console window. When finished writing the firmware the ESP will restart and connect to your WiFi.
All good so far, now configure the device in Home Assistant.
Configure device in Home Assistant
Home Assistant will automatically recognize the ESP on the network and notify you about the new device found. Click on the notification or click Configuration, Integrations. Find the new discovered device and click configure.
Provide the OTA password that you set during step 3 when you created the node in ESPHome.
Home Assistant will now add your ESP as a new device, there is not much you can do with the device as there are no entities to control.