Servo Motor PWM Driver Module I2C 12-Bit PCA9685

Features:

• I2C Communication: Uses only two wires (SCL, SDA) to control up to 16 PWM outputs.
• 16 Independent Channels: Supports simultaneous control of up to 16 servo motors or LEDs.
• 12-Bit Resolution: Offers fine control with 4096 PWM steps for accurate positioning.
• Output Enable (OE): Provides a way to disable all outputs instantly via a dedicated pin.
• Dual Input Pins: Allows easy chaining of multiple modules.
• Standard PWM Ports: Each channel includes V+, GND, and PWM signal pins for organized wiring.
• Frequency Adjustable: PWM frequency can be changed to suit servos or LED dimming.
• Flexible Power Options: Supports external power for high-current servos (up to 6V).
• Arduino Compatible: Easily integrates with Uno, Nano, and other I2C-supported boards.

Specifications:

Pinout:

I2C Addressing (A0–A5):

Each PCA9685 module has configurable address pins (A0 to A5) allowing up to 62 modules on a single I2C bus. Default address: 0x40.

• A0–A5: Pull high (default = 1), pull low = 0
• Example: A0 low, others high → Address = 0x41
• Example: A1 low, A0 low → Address = 0x43

Principle of Operation:

• Each of the 16 channels uses 12-bit PWM to control servo position or LED brightness.
• Uses the I2C bus for communication, allowing multiple modules on the same line.
• Each PWM signal is generated independently, but they all share the same frequency.
• Servo motors receive pulses between ~500µs (0°) and ~2500µs (180°).

Applications:

• Robotics: Control limbs or robotic arms with multiple servos.
• Animatronics: Smoothly animate faces, puppets, and creatures.
• Model Making: RC cars, planes, boats with extensive servo use.
• Automation: Open/close mechanisms in smart home systems.
• Educational: Great for students learning I2C, PWM, and servos.
• Lighting: Use PWM for dimming effects in LED projects.

Typical Circuit:

Library Installation:

1. Open Arduino IDE
2. Go to Sketch > Include Library > Manage Libraries…
3. Search for Adafruit PWM Servo Driver
4. Install the Adafruit_PWMServoDriver library

Sample Arduino Code:

#include "Wire.h"
#include "Adafruit_PWMServoDriver.h"

#define nbPCAServo 16

int MIN_IMP[nbPCAServo] = {500};
int MAX_IMP[nbPCAServo] = {2500};
int MIN_ANG[nbPCAServo] = {0};
int MAX_ANG[nbPCAServo] = {180};

Adafruit_PWMServoDriver pca = Adafruit_PWMServoDriver(0x40);

void setup() {
  Serial.begin(9600);
  Serial.println(F("Initialize System"));
  pca.begin();
  pca.setPWMFreq(60);  // 60 Hz for analog servos
}

void loop() {
  pcaScenario();  // Test movement
}

void pcaScenario() {
  for (int i = 0; i < nbPCAServo; i++) {
    Serial.print("Servo "); Serial.println(i);
    for (int pos = 1500; pos < MAX_IMP[i]; pos += 10) {
      pca.writeMicroseconds(i, pos);
      delay(10);
    }
    for (int pos = MAX_IMP[i]; pos > MIN_IMP[i]; pos -= 10) {
      pca.writeMicroseconds(i, pos);
      delay(10);
    }
    for (int pos = MIN_IMP[i]; pos < 1500; pos += 10) {
      pca.writeMicroseconds(i, pos);
      delay(10);
    }
    pca.setPin(i, 0, true); // Disable output
  }
}

int jointToImp(double x, int i) {
  int imp = (x - MIN_ANG[i]) * (MAX_IMP[i] - MIN_IMP[i]) / (MAX_ANG[i] - MIN_ANG[i]) + MIN_IMP[i];
  return constrain(imp, MIN_IMP[i], MAX_IMP[i]);
}

Comparison with L293D: