Code:
/*
Made by KinCony IoT: https://www.kincony.com
Program functionality:
This program uses ESP32-S3 to control two PCA9555 I/O expander chips via I2C,
controlling a total of 32 relays. The first PCA9555 chip has an I2C address of 0x21
and controls relays 1-16, while the second PCA9555 chip has an I2C address of 0x22
and controls relays 17-32.
The relays are turned ON (set to low) and OFF (set to high) in sequence with a small
delay between each operation. The program reads and prints the current state of the
relays to the serial monitor after each change.
*/
#include <PCA95x5.h>
// Initialize two PCA9555 objects for controlling 32 relays
PCA9555 ioex1; // 1-16 relays (I2C address 0x21)
PCA9555 ioex2; // 17-32 relays (I2C address 0x22)
void setup() {
// Start serial communication for debugging
Serial.begin(115200);
delay(10);
// Initialize the I2C bus with GPIO 11 as SDA and GPIO 10 as SCL, 100kHz frequency
Wire.begin(11, 10, 100000);
// Configure the first PCA9555 chip (1-16 relays)
ioex1.attach(Wire, 0x21); // Set I2C address to 0x21
ioex1.polarity(PCA95x5::Polarity::ORIGINAL_ALL); // Set polarity to normal (no inversion)
ioex1.direction(PCA95x5::Direction::OUT_ALL); // Set all pins as output
ioex1.write(PCA95x5::Level::H_ALL); // Initialize all outputs to HIGH (relays OFF)
// Configure the second PCA9555 chip (17-32 relays)
ioex2.attach(Wire, 0x22); // Set I2C address to 0x22
ioex2.polarity(PCA95x5::Polarity::ORIGINAL_ALL); // Set polarity to normal (no inversion)
ioex2.direction(PCA95x5::Direction::OUT_ALL); // Set all pins as output
ioex2.write(PCA95x5::Level::H_ALL); // Initialize all outputs to HIGH (relays OFF)
delay(50); // Wait for settings to take effect
}
void loop() {
// Control the first PCA9555 chip (1-16 relays)
for (size_t i = 0; i < 16; ++i) {
Serial.print("set port low (chip 1): "); // Turning ON the relay
Serial.println(i);
ioex1.write((PCA95x5::Port::Port)i, PCA95x5::Level::L); // Set the relay to LOW (ON)
Serial.println(ioex1.read(), BIN); // Print the current state of all relays (in binary)
delay(50); // Small delay between each relay activation
}
// Control the second PCA9555 chip (17-32 relays)
for (size_t i = 0; i < 16; ++i) {
Serial.print("set port low (chip 2): "); // Turning ON the relay
Serial.println(i + 16); // Display relay numbers 17-32
ioex2.write((PCA95x5::Port::Port)i, PCA95x5::Level::L); // Set the relay to LOW (ON)
Serial.println(ioex2.read(), BIN); // Print the current state of all relays (in binary)
delay(50); // Small delay between each relay activation
}
// Turn off the first PCA9555 chip (1-16 relays)
for (size_t i = 0; i < 16; ++i) {
Serial.print("set port high (chip 1): "); // Turning OFF the relay
Serial.println(i);
ioex1.write((PCA95x5::Port::Port)i, PCA95x5::Level::H); // Set the relay to HIGH (OFF)
Serial.println(ioex1.read(), BIN); // Print the current state of all relays (in binary)
delay(50); // Small delay between each relay deactivation
}
// Turn off the second PCA9555 chip (17-32 relays)
for (size_t i = 0; i < 16; ++i) {
Serial.print("set port high (chip 2): "); // Turning OFF the relay
Serial.println(i + 16); // Display relay numbers 17-32
ioex2.write((PCA95x5::Port::Port)i, PCA95x5::Level::H); // Set the relay to HIGH (OFF)
Serial.println(ioex2.read(), BIN); // Print the current state of all relays (in binary)
delay(50); // Small delay between each relay deactivation
}
}
