Simple ESPHome Configuration for Powerstrip

The microcontroller inside the smart powerstrip is programmed using ESPHome: a configuration file describes the circuit, and what the microcontroller needs to do.

If you are not familiar with ESPHome and don’t know what a configuration is, you may want to head over to this ESPHome Introduction. In a nutshell, a configuration is the programming of your microcontroller, and as you see, with ESPHome there is no complex C++ code. You simply describe how you wired up your hardware - done.

In this article, I walk you through creating a simple configuration to implement a number of switches. In this configuration, each switch operates exactly one GPIO.

Basic ESPHome Configuration

The microcontroller controls a number of switches that in turn switch distinct GPIOs.

This makes the ESPHome configuration very simple. Here is a basic configuration for six sockets using GPIOs available on a typical ESP32 DevKitC board (which I am using below for testing):

switch:
  - platform: gpio
    pin: GPIO4
    name: "LightSwitchSSR1"
    inverted: true

  - platform: gpio
    pin: GPIO13
    name: "LightSwitchSSR2"
    inverted: true

  - platform: gpio
    pin: GPIO14
    name: "LightSwitchSSR3"
    inverted: true

  - platform: gpio
    pin: GPIO16
    name: "LightSwitchSSR4"
    inverted: true

  - platform: gpio
    pin: GPIO17
    name: "LightSwitchSSR5"
    inverted: true

  - platform: gpio
    pin: GPIO20
    name: "LightSwitchSSR6"
    inverted: true

Adjustments

You may want to adjust this configuration in three places:

• GPIO: I chose the general purpose GPIOs that are available with ESP32 microcontrollers. If you are using a different microcontroller, adjust the GPIOs to the ones that can be used with your microcontroller. Below you can find an example for a ESP32-S2 Mini.
• Inverted: The solid state relais I use are low level trigger: to turn them on, the GPIO signal must be low (high turns them off). With inverted: true I ask ESPHome to pull the GPIO low when the switch is on, and vice versa. If you are using a high level trigger relais, simply remove this line for each GPIO.
• Name: Obviously, you can name your entities as you wish. The name you pick will later (in Home Assistant) become the default name for the switch. You can also rename it later.

Test Driving Microcontroller

Do not connect any components to your microcontroller. Power it up with its USB connection, then install the configuration to your microcontroller.

Once the new firmware is uploaded and the microcontroller has rebooted, Home Assistant auto-detects your new device. Make sure you approve adding your new device to Home Assistant when asked.

Once done, it is now time to go and grab a coffee. Give Home Assistant a few minutes to fully import your new ESPHome device.

If you start working right away with a freshly imported device in Home Assistant, it is not ready yet, and its entities may be missing, or are incomplete. It takes a few minutes for the import to be fully completed.

Creating Test Environment

Before connecting any component or hardware to your microcontroller, first test its basic functionality, and set up a test dashboard.

1. In Home Assistant, go to Settings, then Devices & services. On the Integrations tab, click ESPHome. You now see all of your imported ESPHome devices.

   

2. Identify your device (mine is called LightSwitch SSR #1), and verify the number of entities reported below its name. There should be 7 entities. If there is just one, you may have to wait a few more minutes for Home Assistant to fully import your device.

   

3. Click on 7 entities. You now see all seven entities and their unique ID names. Six of them represent the six switches you defined in your configuration. The seventh entity is added by default and can update the microcontroller firmware.

   

4. Next, add a new dashboard in Home Assistant, and add the six entities that represent your six switches to the dashboard. You may rename your dashboards’ default name HOME to something better. I called my dashboard TestSwitch. Your dashboard is easily accessible via the Home Assistant sidebar on the left side of the Home Assistant screen.

   

Testing Switch Logic

You now have a great test environment where you can change any of the switches and verify the results:

• Slide a switch to see if it stays that way. When it slides back after a moment, then your microcontroller may be offline or not reachable.

• Click on the icon in front of a switch. This opens a larger version of the switch control that tells you when this switch was changed the last time. Play with the switches, and verify that the logging works as expected.

  

Testing Logic Levels

Once that works, it’s now time to test the actual GPIOs on your microcontroller.

Hook up a multimeter to one of the GPIOs you assigned to a switch, and to GND.

Make sure you set your multimeter to a voltage range that can handle 5V before you connect the multimeter to a GPIO. Always disconnect the multimeter before you turn it off again. Else, it may get destroyed: when you try and move its knob to OFF, it may switch to lower voltage ranges first (before it eventually reaches the OFF position). When the measured input signal is high, the ADC in cheap multimeters will be irreversibly damaged.

The multimeter should show either 0V (low) or something close to 3.3V (high). When you change the switch in your test dashboard that is associated with the GPIO you measure, the voltage should change.

If you used inverted: true in your configuration, the GPIO should show be low (and the multimeter should show 0V) when the switch is turned ON.

Test this for all six GPIOs to make sure your logic works as intended.

Verify that the GPIO logic level matches the logic level your relais requires. If the logic levels are mixed up, remove inverted: true from your configuration.

Production Configuration

Once testing succeeded, it’s time to design a production powerstrip. The ESP32 DevKit4 microcontroller is bulky and expensive. A much cheaper, more powerful and very much smaller alternative is the ESP32-S2 Mini. This board is so small it fits easily even in tight enclosures.

These are the microcontroller-related parts of the configuration for a ESP32-S2 Mini:

substitutions:
  name: "powerstrip4-1"
  friendly_name: '4er PowerStrip #1'

esphome:
  name: "powerstrip4-1"
  friendly_name: "4er PowerStrip #1"
  min_version: 2024.6.0
  name_add_mac_suffix: false
  platformio_options:
    board_build.flash_mode: dio
  project:
    name: esphome.web
    version: dev

esp32:
  board: lolin_s2_mini
  variant: ESP32S2
  framework:
    type: arduino

Refining the Configuration

For production, the ESPHome configuration was refined a little bit:

• Icon: each switch received a meaningful icon that later appears in Home Assistant and on your dashboards
• Restore Mode: each switch received a restore mode, so when the powerstrip is plugged out and loses power, it remembers the switch state and returns to the previous state when plugged in again.
• Status LED: the built-in LED on the microcontroller board was wired up as status LED that now blinks slowly while the microcontroller connects, and turns off once remote connectivity is established. The LED can now also be manually controlled like a switch.

Here is the final ESPHome configuration:

light:
  - platform: status_led
    name: "Status LED"
    id: esp_status_led
    icon: "mdi:alarm-light"
    restore_mode: ALWAYS_OFF
    pin:
      number: GPIO15
      inverted: false
      
switch:
  - platform: gpio
    pin: GPIO2
    name: "Switch1"
    icon: "mdi:power-socket-eu"
    restore_mode: RESTORE_DEFAULT_ON
    inverted: true

  - platform: gpio
    pin: GPIO3
    name: "Switch2"
    icon: "mdi:power-socket-eu"
    restore_mode: RESTORE_DEFAULT_ON
    inverted: true

  - platform: gpio
    pin: GPIO4
    name: "Switch3"
    icon: "mdi:power-socket-eu"
    restore_mode: RESTORE_DEFAULT_ON
    inverted: true

  - platform: gpio
    pin: GPIO5
    name: "Switch4"
    icon: "mdi:power-socket-eu"
    restore_mode: RESTORE_DEFAULT_ON
    inverted: true

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