# Integrate the Carbon Dioxide (CO2) Module

# Integrate the Carbon Dioxide (CO2) Module

Enhance your Everything Presence Lite with CO₂ monitoring.


:::info
The CO₂ module is supported in Home Assistant. Homey support depends on your Homey app version.

:::

## Install the CO₂ Sensor

### What you need

* **Everything Presence Lite (powered off)**
* **CO₂ sensor module**

### Identify GPIO Pins


1. Locate the **GPIO pins** in the bottom corner of the Lite board.
   * The layout may vary depending on your board revision. ![](https://docs.everythingsmart.io/api/files.get?sig=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJrZXkiOiJ1cGxvYWRzLzEyODlhY2JjLWM2NWItNGNhNy05YjA0LWI3YjZmYzc5ZjFiNS84YWRkZGM0OC0yYzRiLTRjZTEtOWVhNC1kNzE1NGIzNDlhNGMvaW1hZ2UucG5nIiwidHlwZSI6ImF0dGFjaG1lbnQiLCJpYXQiOjE3OTM2ODIwMDAsImV4cCI6MTc5Mzc2ODQwMH0.Gfv-tVewTFQTlMVFKs_ZoUtBM8sTRGra4iVyAiKMh6c)
2. Align the **CO₂ sensor module** with the pins, ensuring:
   * **3.3V** on the sensor matches **3.3V** on the board.
   * **GND (Ground)** on the sensor matches **GND** on the board.
   * **SDA** (GPIO26) and **SCL** (GPIO27) pins are correctly aligned.
3. Firmly **push the CO₂ module onto the GPIO pins**. ![](https://docs.everythingsmart.io/api/files.get?sig=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJrZXkiOiJ1cGxvYWRzLzEyODlhY2JjLWM2NWItNGNhNy05YjA0LWI3YjZmYzc5ZjFiNS84YjBhZGFlYy0zMWQ3LTQ0MzEtYjJjZC1jNDRjZWEzOTJhOTMvaW1hZ2UucG5nIiwidHlwZSI6ImF0dGFjaG1lbnQiLCJpYXQiOjE3OTM2ODIwMDAsImV4cCI6MTc5Mzc2ODQwMH0.DB93XRbkGt1EqDdsmV4iWpr_quluRqHYyHBH-y4Xbz4)

## Install the CO₂ Firmware

To enable CO₂ monitoring, install the **CO₂ firmware version** on Everything Presence Lite.


1. Using the flasher below select the following settings.
2. Choose **LD2450** as the default mmWave sensor.
3. Select the **CO₂** module.
4. Choose between:
   * **Bluetooth firmware** (if you need Bluetooth features).
   * **Non-Bluetooth firmware** (if Bluetooth is not required).
5. Click **Connect** and follow the on-screen instructions.

[Link to install CO2 sensor](https://docs.everythingsmart.io/s/products/doc/restore-or-update-your-epl-to-factory-settings-using-a-computer-orj7PBBOJZ)

## Verify CO₂ Sensor in Home Assistant

Once the firmware update is complete, the CO₂ sensor should automatically appear as an entity in Home Assistant.

## Using the CO₂ Sensor

The CO₂ sensor measures carbon dioxide concentration in parts per million (ppm). Here's what typical readings mean:

| CO₂ Level | Meaning |
|-----------|---------|
| 400-450 ppm | Fresh outdoor air |
| 450-700 ppm | Good indoor air quality |
| 700-1000 ppm | Acceptable, consider ventilation |
| 1000-2000 ppm | Poor air quality, open windows |
| 2000+ ppm | Significantly elevated, improve ventilation immediately |

**Tip:** CO₂ levels are a great indicator of ventilation quality. Use automations to trigger fans or send notifications when levels exceed your preferred threshold.

## Calibrating the CO₂ Sensor

The SCD40 CO₂ sensor is factory-calibrated but may need recalibration over time for best accuracy.

### When to Calibrate

* After installing the sensor for the first time
* If readings seem consistently off by more than 50-100 ppm
* After the sensor has been stored for a long time
* Periodically (every 6-12 months) for best accuracy

### How to Calibrate


1. Place the sensor in fresh outdoor air, or near an open window with good airflow
2. Wait at least 5 minutes for the sensor to stabilize
3. In Home Assistant, find the **Calibrate CO2** button entity
4. Press the button to calibrate to 419 ppm (current atmospheric CO₂ average)

**Important:** The sensor must be exposed to fresh air during calibration. Indoor air typically has higher CO₂ levels due to human respiration.

---

**Documents**

- [EP1 vs EPL: Which Sensor is Right for You?](https://docs.everythingsmart.io/s/products/doc/ep1-vs-epl-which-sensor-is-right-for-you-5B3RxiY3Kp)
- [Everything Presence One (EP1)](https://docs.everythingsmart.io/s/products/doc/everything-presence-one-ep1-3R178yZSUP)
- [Everything Presence Pro](https://docs.everythingsmart.io/s/products/doc/everything-presence-pro-nh3fIXmow9)
- [Everything Presence Lite (EPL)](https://docs.everythingsmart.io/s/products/doc/everything-presence-lite-epl-ZVnBzYzuX2)
- [Zone Configurator](https://docs.everythingsmart.io/s/products/doc/zone-configurator-93b9scGsa2)
- [Knowledge Base Articles](https://docs.everythingsmart.io/s/products/doc/knowledge-base-articles-KnRRmk4zvt)