Build a cheap air quality meter using ESPhome, Home Assistant and a particulate matter sensor

This article will provide a walkthrough of how you can build a Particulate Matter Air Quality meter that integrates with your Home Assistant for under 20$, without any soldering or coding skills needed.

The sensor will provide multiple air-quality measurements directly visible in Home Assistant.

After seeing all kinds of air purifiers in the market, like the one from Xiaomi and Philips. I got interested in the topic air quality. First, I needed to learn more about how and what to measure, followed by actually measuring the air quality in my home. I don’t want to buy a air purifier if the quality of the air in my home is not bad. But how do you measure air quality?

What is a Particulate Matter sensor?

My search started with looking for a particulate matter sensor. A particulate matter sensor measures tiny particles or droplets in the air that have a specific size in microns or micrometers (µm). Like inches, meters and miles, a micron is a unit of measurement for distance. There are about 25,000 microns in an inch.

Particulate matter is the sum of all solid and liquid particles suspended in air many of which are hazardous. This complex mixture includes both organic and inorganic particles, such as dust, pollen, soot, smoke, and liquid droplets. These particles vary greatly in size, composition, and origin.

Source: www.greenfacts.org

Particulate matter (PM) is generally classified into two main size categories: PM10 and PM2.5. As an example, the particulate classified as PM2.5 is the size of 2.5 µm and would be thirty times smaller than that of a human hair.

Continue reading “Build a cheap air quality meter using ESPhome, Home Assistant and a particulate matter sensor”

Why C-suite alignment is necessary for smarter technology investment decisions [publication]

This week my article on CIO and CMO alignment is necessary for smarter technology investment decisions got featured on Digitalisation World.

Article published on Digitalisation works

When it comes to smarter technology investment decisions, how can CIOs and CMOs find common ground? Learn more about the importance of having an expert that can speak to IT and marketing, read the article.

Bellfire home automation project

This article provides you with an overview and links of all articles published around the fireplace project that was presented during the Home Assistant Conference 2020.

Slides

View Automate Everything! How to make your stupid device smart on Notist.

Introduction articles

The steps

Shopping list

  1. The ESPboard: ESP8266 board or ESP32 if you also want to use Bluetooth features on AliExpress.com
  2. The 4 channel relay board. Make sure you select the 5V version The relay: 5v relay board AliExpress.com
  3. If you don’t want to solder order:
    – Mini breadboards AliExpress.com
    – Dupont cables male-female AliExpress.com

Step 5: Wire the relays to the fireplace

This article is part of the Make your Bellfire fireplace smart project that I presented during the Home Assistant Conference 2020.

It’s time to execute the final step, you can find all steps in the overview how it all going to work article.

Now everything is set. We now can connect the relays to the fireplace and light up the fireplace using Home Assistant.

The wiring

Again very basic wiring is needed.  I need to make sure that I connect the wiring to map the pinout of the fireplace.

If we look at the pin-out on the fireplace, going bottom up.

  • Pin 0 is the common circuit and need to be connected to the COM of all three relay.
  • Pin 1 wires to the Normal Open (NO) port of relay 1
  • Pin 2 wires to the Normal Open (NO) port of relay 3
  • Pin 2 wires to the Normal Open (NO) port of relay 3

See wiring details below.

wiring

That’s it! Now sit back, open Home Assistant and press the ignite button. Your fireplace will now lite up.

Step 4: Configure ESPHome to control the relays from Home Assistant

This article is part of the Make your Bellfire fireplace smart project that I presented during the Home Assistant Conference 2020.

It’s time to execute the fourth step, you can find all steps in the overview how it all going to work article.

The wiring is now ready, let’s expose three switches to Home Assistant to control the relays.

Expose pins as switches

Open ESPHome and click EDIT on your node. The ESPHome configuration editor will now show. Add following configuration in the bottom of the configuration.

switch:
  - platform: gpio
    pin: GPIO13   #D7
    name: "IN1" 
    id: IN1
  - platform: gpio 
    pin: GPIO12  #D6
    name: "IN2"
    id: IN2
  - platform: gpio 
    pin: GPIO14  #D5
    name: "IN3" 
    id: IN3

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.

- platform: template
    name: "Fireplace_ignition"
    id: Fireplace_ignition
    turn_on_action:
      - then:
        - switch.turn_on: IN1
        - switch.turn_on: IN3
        - delay: 2s
        - switch.turn_off: IN1
        - switch.turn_off: IN3
        - switch.template.publish:
            id: Fireplace_ignition
            state: ON
    turn_off_action:
      - then:
        - switch.turn_on: IN1
        - switch.turn_on: IN2
        - switch.turn_on: IN3
        - delay: 1s
        - switch.turn_off: IN1
        - switch.turn_off: IN2
        - switch.turn_off: IN3
        - switch.template.publish:
            id: Fireplace_ignition
            state: OFF

Press the Upload to compile, upload and flash the ESP with the new firmware. Test your new switch and verify that the relay react as expected.

Now it’s time to for the last step, time to wire the relays to the fireplace.

Step 3: Wiring the ESP to the relay

This article is part of the Make your Bellfire fireplace smart project that I presented during the Home Assistant Conference 2020.

It’s time to execute the third step, you can find all steps in the overview how it all going to work article.

To control the relay we need to provide high or low power to the IN ports of the board. This board has four relays. In my example I only need to use three relays.

Wiring the relay board to the ESP is easy.

Powering the relay board

The relay board needs 5v power. We will power the relay board directly from the ESP using the 5v VIN pin.

Controlling the relays

Pin D5, D6, and D7 will be used to control the three relays on the board.

See wiring image below for more details.

The wiring is now ready, let’s expose three switches to Home Assistant to control the relays. Read the next article.

Step 2: Flash ESP chip with ESPHome node firmware

This article is part of the Make your Bellfire fireplace smart project that I presented during the Home Assistant Conference 2020.

It’s time to execute the second step, you can find all steps in the overview how it all going to work article.

Now we need to load the configuration of your node to the ESP board. I recommend flashing the firmware from your local laptop and a USB cable, using the Flasher tool from ESPHome. Let’s get started.

Compile firmware

We need to start by compiling the firmware that we’ll use to flash the ESP chip.
In ESPHome select the menu of your node (three dots (…) in the top right of your node) and select Compile.

ESP home will now compile your firmware. After the compilation is finalized you can download the firmware.  Download and store the file somewhere you can find it later on.

Flash ESP with compiled firmware

Now we’re going to flash the ESP firmware with your compiled firmware.

  • Go to the esphome-flasher GitHub page and download the flasher for the OS you’re using:
    https://github.com/esphome/esphome-flasher/releases
  • Connect your ESP board with USB to your laptop.
  • Open the flasher tool
    • 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.
The ESP will be ready after it states that it’s ready for Over-The-Air Updates and that he API server is ready.

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.

In the next article, we’ll wire the relay to the ESP board.