Connecting the Components - Air Quality Monitoring Station Series, Episode 7

Lesson objectives

The purpose of this lesson is to guide students through the physical setup and connection of the components in the IoT air quality monitoring station. By the end of this lesson, students will have connected the ESP32 microcontroller and AHT10 temperature and humidity sensor to a breadboard, ready for testing and programming.

Overview of components and connections

In previous lessons, we covered the individual components of the system, such as the ESP32, AHT10 sensor, and TFT display. Now it is time to assemble them into a working circuit.

The components are connected so they can communicate and perform their specific tasks:
The AHT10 sensor collects temperature and humidity data.
The ESP32 processes the data and manages communication between the components.
The TFT display shows the collected data for immediate feedback.

List of required components:

	AHT10 high-precision temperature and humidity sensor
	TTGO T-Display ESP32 16MB with WiFi, Bluetooth and 1.1" color LCD screen
	Dupont cables, 40 pcs

Step-by-step guide to connecting the components

1. ESP32 microcontroller

• The ESP32 connects to the AHT10 sensor via the I2C protocol and to the TFT display via the SPI protocol.

2. AHT10 temperature and humidity sensor

• The AHT10 sensor communicates with the ESP32 via the I2C protocol and requires the following connections:
  • VCC: Connects to 3.3V on the ESP32 to supply power to the sensor.
  • GND: Connects to GND on the ESP32.
  • SDA (Data Line): Connects to GPIO 21 on the ESP32 (the I2C SDA pin).
  • SCL (Clock Line): Connects to GPIO 22 on the ESP32 (the I2C SCL pin).

3. TFT display

• The TFT display is soldered directly onto the board, so no additional connections need to be made manually.

Tips for a tidy and organized setup

Use a breadboard: A breadboard makes it easy to connect and organize components without soldering. Place the TTGO T-Display board and AHT10 sensor on the breadboard and connect the sensor using jumper wires. The TFT display is already soldered onto the board.

Double-check pin connections: Make sure the ESP32, AHT10, and TFT display are connected correctly. A single incorrect connection can stop the system from working.

Power supply:

• The ESP32 should receive sufficient power via a USB connection for both the sensor and the screen.
• If more components are added, an external power supplymay be necessary.

Keep wires organized: A tidy setup makes troubleshooting easier and reduces the risk of accidental disconnections.

Connection summary

AHT10 sensor: Connected to 3.3V, GND, GPIO 21 (SDA), and GPIO 22 (SCL).
TTGO T-Display board: Connected to a PC/laptop via USB-C for power and data.

These connections ensure that the ESP32 can communicate with both the sensor and the display, process the data, and visualize it in real time.

Conclusion

In this lesson, we have successfully connected the core components of our IoT project: the ESP32 microcontroller, AHT10 sensor, and TFT display. These connections form the foundation for data collection and visualization in the upcoming lessons.

In the next lesson, we will focus on the Arduino IDE and take the first step in programming our air quality monitoring station. 

About the measurements: The station in this series measures temperature and relative humidity using the AHT10. These are indoor climate readings, not direct measurements of CO2, VOCs, or particles. The series name “air quality monitoring” should be understood with this limitation.