Dec 23, 2022

7 min read

Indoor Air quality analysis using ESP32 and Bytebeam cloud

people typically spend more than 90% of their time in indoor environments. Monitoring indoor air quality parameters like CO2 plays an important role in a healthy lifestyle.

Indoor air quality (IAQ) monitoring is a very often talked about topic nowadays as it critically affects a person’s health, comfort, and safety.

People who might be at their homes, workplace offices, etc. typically spend more than 90% of their time in indoor environments. So, It is not only directly related to occupational health but also has a significant impact on the quality of life of people.

One of the key indicators of indoor air quality is Carbon dioxide (CO2) and it has a substantial influence on public health. Thus, regular monitoring and Analysis of indoor air quality parameters like CO2 becomes essentially important to regulate occupational health and ensure better working environments

Some of the Factors affecting indoor CO2 levels include:

Number of people in a room
Person’s metabolic rate
Amount of time a person spent in the room
Ventilation rate (exchanges per hour with fresh outside air)

Keeping in mind all the factors affecting indoor CO2 levels we will be going through a step-by-step guide to creating an IoT solution for CO2, temperature, and Humidity monitoring using ESP32 and Bytebeam Cloud. In this blog we will be demonstrating the following:

Setting up ESP32
Interfacing CO2 sensor and Temperature and Humidity Sensor with ESP32
Interfacing relay with ESP32 to control window blinds to regulate ventilation.
Setting Up Bytebeam ESP-IDF SDK.
Integrating ESP32 with Bytebeam Cloud
Visualizing CO2 sensor data on Bytebeam Cloud Dashboard.

So Let’s get started.

Hardware and Software Specifications

Hardware Specification

Software Specification

Setting Up Bytebeam Cloud

Bytebeam is a fully managed cloud platform. Which serves all cloud needs from device management to dashboard, Handling actions, and notification to OTA updates. It provides the following features

Device Registry
Over The Air Updates
Configuration Management
Device to mobile communication
Web Dashboard
Role-based Access controls

If you are new to the Bytebeam IoT cloud platform. Go through the getting started with bytebeam tutorial to dive deep into the concepts of Bytebeam.

I hope you found the getting started guide useful and are aware of the concepts of Bytebeam cloud.

Next, as we are using temperature, humidity, and CO2 parameters. We need to configure stream according to our project in Bytebeam cloud console. For that go to Admin -> Streams and add temperature, humidity, and carbon in the column name with their respective data type.

Now we need to download a device provisioning file from the console. We will need this file later for device provisioning. For that go to Device Management and click on Download config.
Rename this file as device_config.json

Setting Up ESP32

Hardware connection

CCS811 CO2 sensor comes with an I2C connection. Connect SDA Pin of CCS811 with GPIO21 of ESP32 and SCL Pin with GPIO 22 of ESP32.
SHT31 Temperature and Humidity Sensor comes with an I2C connection. Connect SDA Pin of ESP32 with GPIO21 of ESP32 and SCL Pin with GPIO 22 of ESP32.
Connect 5V SSD Relay with GPIO 4

Project Setup

Clone esp-bytebeam-sdk using the git clone command.

git clone https://github.com/bytebeamio/esp-bytebeam-sdk.git

The Repository contains the following directories
components: This directory contains bytebeam_esp_sdk as a component that you can add to your ESP application
Provisioning: example to push device JSON got from bytebeam cloud to SPIFFS.
example: example directory contains a list of examples, some of the important ones are
Now clone the indoorAirQuality example.

git clone https://github.com/vbshightime/indoorAirQuality

Provision ESP32 with device config data

Earlier in this guide, we had provisioned a new device in the bytebeam cloud console and downloaded a JSON file. We need to flash this file to SPIFFS to connect our device to the cloud.

Now navigate to the provisioning example and create a new folder config_data inside it.

Now open the ESP-IDF terminal and navigate to the provisioning project.
Clear entire flash

idf.py -p PORT flash monitor

Getting CO2 Sensor and temperature and humidity sensor values

Navigate to indoorAirQuality-> main -> app_main.c.
include ccs811 driver and sht31 driver

#include "ccs811/ccs811.h"
#include "sht31.h"

inside app_main initialise the ccs811 CO2 sensor

if (init_ccs811()){
        printf("\nInitialized!!!\n");
    }
    else{
        printf("\nNO Initialized\n");
    }

Now initialise the SHT31 sensor

if (sht31_init()) {
        printf("Initialised SHT31");
    } else {
        printf("Could not initialize SHT3x sensor\n");
    }

We will get the Co2 values using the get_ccs811() function.
We will get temperature and humidity values using getSHTValues().

getSHTValues()

Now add Co2, temperature and humid values to the payload

carbon_json = cJSON_CreateNumber(get_ccs811(0)); 
cJSON_AddItemToObject(device_shadow_json, "carbon", carbon_json); 
humid_json = cJSON_CreateNumber(humidity); 
cJSON_AddItemToObject(device_shadow_json, "humidity", humid_json); 
temperature_json = cJSON_CreateNumber(temperature); 
cJSON_AddItemToObject(device_shadow_json, "temperature", temperature_json);

Creating an action handler to control blinds

Increasing levels of CO2 in the workspace can cause laziness and sleepiness. So to regulate the flow of fresh air. We are using a relay to open and close window blinds to improve airflow.

We will trigger this action whenever the CO2 levels cross a particular threshold(1000PPM)

We can create an action handler using these simple steps.

We have connected the 5V SSD relay to GPIO 4

#define BLINK_GPIO 4

Now flash and upload the indoorAirQuality example
In the configure_blinds function, we will configure the GPIO mode as GPIO_MODE_OUTPUT

static void configure_blinds(void)
{
   gpio_reset_pin(BLINK_GPIO);
   gpio_set_direction(BLINK_GPIO, GPIO_MODE_OUTPUT);
}

Add an action handler using the bytebeam_add_action_handler function. It contains the following arguments
bytebeam_client: structure containing host, port, certificates and device id information
toggle_blinds: handler function to toggle relay
toggle_blind: action name

bytebeam_add_action_handler(&bytebeam_client, toggle_blinds, "toggle_blind");

Flash and Upload

Now flash and upload the example

Idf.py -p PORT flash monitor

In the next section, we will add “toggle_blind” actionon the bytebeam cloud.

Adding action on Bytebeam cloud

Login to your bytebeam cloud account and go to the Device Management tab
Here you can see preconfigured actions like Update Firmware, Update Configuration, and Push File.
In Type edit text we need to write down the action name i.e. toggle_board_led in our case. Earlier in Configuring actions in the ESP32 section we created an action handler with toggle_blind as the action name.
Now you can find newly created actions on the action list

Triggering an Action

We need to follow these easy steps to trigger an action:

Navigate to the Devices tab under Device Management
Click on the checkboxes to select the list of devices you want to trigger the Action

Click on the Action button you want to trigger. In our case, we have selected a device with #id 1 and triggered ‘Toggle Blind’ Action.
In the Last Action column, you can see the Action status as Queued and you can monitor the progress of the action from the progress bar
The Action will be sent to the selected Devices now. If the device is offline when the Action is triggered, the system will retry sending Actions to the device every 5s.
Here action we need to perform is to automate our windows blinds when the CO2 level crosses a threshold.
Earlier before triggering the action. The status was “Blinds are closed”.

After triggering Toggle Blind action. The status changed to Blinds are open. And action status changed to Completed.

Data Visualization in Bytebeam cloud

After a successful connection of ESP32 with Bytebeam cloud. We can see the recent device shadow and heartbeat on the cloud console.

Next, create a Dashboard of your choice We have made use of line charts and gauges to create our dashboard. You can use it as per your choice.

Guidelines to Check CO2 levels in a workplace

Escalation of CO2 levels in a workplace can affect your health in different ways. The CO2 levels can differ based on occupancy, ventilation and respiration rate. The increasing level can also cause laziness, sleepiness, dizziness etc.

As we can see in the graph variation in CO2 level as the occupancy and ventilation in the room changes

Conclusion

We are officially launching our ESP-SDK to connect the ESP-32 device to the Bytebeam cloud. ESP-SDK is live on the product hunt. I hope you find this guide useful. We will come up with more interesting tutorials and maker content. Stay tuned.