Unit AC Measure Home Assistant Integration

This tutorial will introduce how to use the Unit AC Measure AC electrical parameter measurement unit with the AtomS3R main controller and integrate it into Home Assistant to achieve real-time monitoring of AC voltage, current, active power, and energy consumption.

Preparation

1. Hardware List

• 1 x Unit AC Measure
• 1 x AtomS3R
• 1 x HY2.0-4P Grove Cable (20cm)
• 1 x Home Assistant Host (Server, Mini PC, NAS, etc.)

2. Software and Versions

• Home Assistant 2026.2.0 or above
• ESPHome Device Builder 2026.2.2 or above

Create Device

1. Open the ESPHome Dashboard. If the initial guidance interface appears, click CONTINUE.

2. Click the green + button in the lower right corner to start creating a new device.

3. Click New Device Setup to enter the device creation wizard.

4. Enter the device name and click NEXT.

5. Select the device type, click ESP32S3.

6. Click SKIP to skip the encryption key setting.

7. Click EDIT to enter the YAML configuration page and customize device functions.

Modify Configuration

External Components Configuration

Add the External Components configuration in the YAML file to load the unit_acmeasure sensor driver.

external_components:
  - source: github://m5stack/esphome-yaml/components
    components: unit_acmeasure
    refresh: 0s

I2C Bus Configuration

Add the I2C component to configure the communication pins between Unit AC Measure and AtomS3R.

i2c:
  sda: GPIO2
  scl: GPIO1
  scan: true

Sensor Configuration

Add the Sensor component to enable AC measurement-related sensor entities.

sensor:
  - platform: unit_acmeasure
    id: acmeasure1
    address: 0x42
    update_interval: 2s
    voltage:
      name: AC Voltage
    current:
      name: AC Current
    power:
      name: Active Power
    apparent_power:
      name: Apparent Power
    power_factor:
      name: Power Factor
    energy:
      name: Energy

Main Parameter Descriptions:

Download and Flash Firmware

Compile Firmware

1. After completing the YAML modification, click SAVE in the upper right corner to save the configuration, then click INSTALL.

2. Select Manual Download in the pop-up window.

3. Wait for the firmware compilation to complete, click Download and select Factory format (Previously Modern) to save the firmware locally.

Flash Firmware

4. Connect AtomS3R to the computer using a USB Type-C cable. Open ESPHome Web and click CONNECT.

5. In the pop-up serial port selection window, select the correct serial port number.

6. Click INSTALL.

7. Select the firmware file downloaded in step 3 and start flashing.

Learn

1. In Home Assistant, click Settings > Devices & Services in sequence to enter the integration management page.

2. Find the Unit AC Measure device in the Discovered area, click CONFIGURE, and follow the wizard to complete the configuration.

3. After the device is added, multiple sensor entities can be seen on the device details page, such as AC Voltage, AC Current, Active Power, Apparent Power, Power Factor, and Energy, along with their real-time values.

4. Finally, add these sensor entities to the dashboard to monitor AC electrical parameters and power consumption in real-time.