Introduction to PAJ7620 Gesture Recognition Module

This project implements a touch-free gesture recognition system using an Arduino UNO, a PAJ7620 Gesture Recognition Module, and an I2C LCD Display. The PAJ7620 is a specialized sensor equipped with built-in gesture recognition processing capabilities that can detect specific hand movements—such as moving up, down, left, right, forward, backward, and circling—without requiring complex machine learning algorithms to run locally on the microcontroller. The Arduino UNO interfaces with both the gesture sensor and the LCD display via the I2C communication protocol, which requires only two data lines (SDA and SCL) alongside power connections. Using the Wire, DFRobot_PAJ7620U2, and LiquidCrystal_I2C libraries, the Arduino continuously polls the PAJ7620 for register updates representing recognized gesture events. When a user swipes their hand in front of the sensor, the PAJ7620 registers the motion and transmits the corresponding data packet to the Arduino over I2C. The microcontroller interprets this data and updates the connected I2C LCD display in real time, rendering the name of the detected gesture on the screen. Because the Arduino UNO operates on 5V logic while the PAJ7620 sensor's I/O pins are rated for a maximum of 3.3V, resistors or level-shifting techniques are incorporated into the wiring to protect the sensor from overvoltage damage while maintaining reliable signal integrity.