How to Use Adafruit PWM Servo Featherwing: Examples, Pinouts, and Specs

The Adafruit PWM Servo FeatherWing is an add-on board designed for use with the Feather ecosystem of development boards. It utilizes the PCA9685 PWM driver to control up to 8 servos, making it an ideal choice for robotics, animatronics, and any project requiring precise motion control. The board's ability to drive multiple servos with a single I2C interface simplifies wiring and conserves valuable GPIO pins on the Feather host board.

• Robotics arms and legs
• Animatronic figures
• Automated art installations
• Remote-controlled vehicles
• Prototyping and educational projects

• Voltage: 3V to 5V logic and power
• Current: 6mA (typical) when not driving servos
• Output Channels: 8 PWM outputs
• Frequency: 40Hz to 1000Hz adjustable PWM frequency
• Resolution: 12-bit resolution for each channel

1. Powering the Board:

   • Connect a 5V-6V power supply to the V+ and GND pins to power the servos.
   • Ensure the Feather board is powered separately as per its requirements.

2. Connecting Servos:

   • Attach the servo's power cable to the V+ and GND pins.
   • Connect the servo's control wire to one of the PWM output pins (PWM 0 to PWM 7).

3. I2C Communication:

   • Connect the SCL and SDA pins to the corresponding I2C pins on the Feather board.
   • If using multiple FeatherWings, set unique I2C addresses using the ADDR pin.

• Do not exceed the recommended voltage for the servos to prevent damage.
• Ensure that the power supply can handle the current draw of all connected servos.
• Use external power when driving multiple or high-power servos to avoid overloading the Feather board's voltage regulator.
• Always disconnect power before making or changing connections.

#include <Wire.h>
#include <Adafruit_PWMServoDriver.h>

// Initialize the PCA9685 using the default address (0x40).
Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver();

void setup() {
  Serial.begin(9600);
  Serial.println("8-channel PWM test!");

  pwm.begin();
  pwm.setPWMFreq(60);  // Set frequency to 60 Hz
}

void loop() {
  // Sweep each servo back and forth
  for (uint16_t pulselen = SERVOMIN; pulselen < SERVOMAX; pulselen++) {
    pwm.setPWM(0, 0, pulselen);
  }

  delay(500);
  for (uint16_t pulselen = SERVOMAX; pulselen > SERVOMIN; pulselen--) {
    pwm.setPWM(0, 0, pulselen);
  }

  delay(500);
}

// Depending on your servo make, the pulse width min and max may vary
#define SERVOMIN  150 // This is the 'minimum' pulse length count (out of 4096)
#define SERVOMAX  600 // This is the 'maximum' pulse length count (out of 4096)

• Servos not responding: Check power connections and ensure the power supply is adequate.
• Jittery servo movement: This can be due to a low-quality power supply or interference on the I2C line.
• I2C communication errors: Ensure there are no address conflicts and that the SDA/SCL lines are connected properly.

• Use a multimeter to verify power supply voltage and servo connections.
• If using long wires for I2C communication, add pull-up resistors to reduce interference.
• Check and re-solder any loose connections or cold solder joints.

Q: Can I control more than 8 servos with this board? A: Yes, by stacking multiple FeatherWings and setting unique I2C addresses, you can control additional servos.

Q: What is the maximum number of boards I can stack? A: You can stack up to 62 boards for a total of 496 servos, limited by the number of available I2C addresses.

Q: Can I use this board with other microcontrollers besides the Feather? A: Yes, as long as the microcontroller supports I2C communication and operates at 3V to 5V logic levels.

Q: Do I need to install any libraries to use this board with an Arduino? A: Yes, you will need to install the Adafruit_PWMServoDriver library available through the Arduino Library Manager.