Office Comfort Sensor Network
Description
The goal of this project is to develop a smart sensor network to help study the overall quality and comfort of office environments, taking measurements that can describe indoor environmental quality, such as temperature, humidity, VOC and CO2 concentration, light temperature and intensity, and sound noise level.
This network sensor is focused on collecting that data to be able to take actions on the specific indicator that needs to be improved, making the office comfortable for everyone, which can lead to better work productivity.
Technical Details
To be able to cover large areas, the devices are interconnected via a Bluetooth Mesh Network, which also provides low power consumption for long battery life. Each device contains various sensors to measure the indoor quality indicators, and are battery powered:
I developed custom libraries to interface with each sensor via the ESP32 microcontroller, using the ESP-IDF:
- SGP30 - tVOC and eCO2 sensor
- BME280 - temperature, humidity and pressure sensor
- AS7262 - light intensity and color temperature sensor
- analog microphone to measure noise level in dB
A custom Bluetooth Mesh model was developed (both client and server models) to be able to transmit the measurements from each device to a gateway node, which relayed the data to an external AWS server via Wi-Fi + MQTT. That data is stored on an InfluxDB time series database, and is consumed on a Grafana dashboard, making the data visible to the end users.
Every device is also equipped with a small OLED screen that shows simple yes/no questions about the user's sense of comfort related to the measured parameters, and a few buttons to answer them. That feedback makes it possible to draw conclusions about the overall user comfort alongside the measured sensor data for that device.
Results
The project was developed in 2020 to obtain a Bachelor's degree in Electrical and Computer Engineering from the University of Sao Paulo, and received an 8/10 final score. All the source code and electronic schematics are available on GitHub.
