piezo_servo.ino

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

// These constants won't change. They're used to give names to the pins used:
const int analogInPin = A0;  // Analog input pin that the potentiometer is attached to
const int analogOutPin = 9; // Analog output pin that the LED is attached to

int sensorValue = 0;        // value read from the pot
int outputValue = 0;        // value output to the PWM (analog out)


// called this way, it uses the default address 0x40
Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver();
// you can also call it with a different address you want
//Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver(0x41);
// you can also call it with a different address and I2C interface
//Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver(0x40, Wire);



// Depending on your servo make, the pulse width min and max may vary, you
// want these to be as small/large as possible without hitting the hard stop
// for max range. You'll have to tweak them as necessary to match the servos you
// have!
#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)
#define USMIN 600 // This is the rounded 'minimum' microsecond length based on the minimum pulse of 150
#define USMAX 2400 // This is the rounded 'maximum' microsecond length based on the maximum pulse of 600
#define SERVO_FREQ 50 // Analog servos run at ~50 Hz updates



// our servo # counter
uint8_t servonum = 0;



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



  pwm.begin();
  /*
    In theory the internal oscillator (clock) is 25MHz but it really isn't
    that precise. You can 'calibrate' this by tweaking this number until
    you get the PWM update frequency you're expecting!
    The int.osc. for the PCA9685 chip is a range between about 23-27MHz and
    is used for calculating things like writeMicroseconds()
    Analog servos run at ~50 Hz updates, It is importaint to use an
    oscilloscope in setting the int.osc frequency for the I2C PCA9685 chip.
    1) Attach the oscilloscope to one of the PWM signal pins and ground on
    the I2C PCA9685 chip you are setting the value for.
    2) Adjust setOscillatorFrequency() until the PWM update frequency is the
    expected value (50Hz for most ESCs)
    Setting the value here is specific to each individual I2C PCA9685 chip and
    affects the calculations for the PWM update frequency.
    Failure to correctly set the int.osc value will cause unexpected PWM results
  */
  pwm.setOscillatorFrequency(27000000);
  pwm.setPWMFreq(SERVO_FREQ); // Analog servos run at ~50 Hz updates



  delay(10);
}



// You can use this function if you'd like to set the pulse length in seconds
// e.g. setServoPulse(0, 0.001) is a ~1 millisecond pulse width. It's not precise!
void setServoPulse(uint8_t n, double pulse) {
  double pulselength;

  pulselength = 1000000; // 1,000,000 us per second
  pulselength /= SERVO_FREQ; // Analog servos run at ~60 Hz updates
  Serial.print(pulselength); Serial.println(" us per period");
  pulselength /= 4096; // 12 bits of resolution
  Serial.print(pulselength); Serial.println(" us per bit");
  pulse *= 1000000; // convert input seconds to us
  pulse /= pulselength;
  Serial.println(pulse);
  pwm.setPWM(n, 0, pulse);
}



void loop() {
  // read the analog in value:
  sensorValue = analogRead(analogInPin);
  // map it to the range of the analog out:
  outputValue = map(sensorValue, 0, 1023, 0, 255);
  // change the analog out value:

  // print the results to the Serial Monitor:
  Serial.print("sensor = ");
  Serial.print(sensorValue);
  Serial.print("\t output = ");
  Serial.println(outputValue);

  // wait 2 milliseconds before the next loop for the analog-to-digital
  // converter to settle after the last reading:
  delay(2);

  if (sensorValue > 100) {
    // Drive each servo one at a time using setPWM()
    Serial.println(servonum);
    for (uint16_t pulselen = SERVOMIN; pulselen < SERVOMAX; pulselen++) {
      pwm.setPWM(servonum, 0, pulselen);
    }



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



    delay(500);



    // Drive each servo one at a time using writeMicroseconds(), it's not precise due to calculation rounding!
    // The writeMicroseconds() function is used to mimic the Arduino Servo library writeMicroseconds() behavior.
    for (uint16_t microsec = USMIN; microsec < USMAX; microsec++) {
      pwm.writeMicroseconds(servonum, microsec);
    }



    delay(500);
    for (uint16_t microsec = USMAX; microsec > USMIN; microsec--) {
      pwm.writeMicroseconds(servonum, microsec);
    }



    delay(500);



    servonum++;
    if (servonum > 1) servonum = 0; // Testing the first 8 servo channels
  }
}