The code below is for the bird project. You can change the chirp function for one of the other sounds defined on the Animal Sounds page.
The code reads the photocell and if the value is less than a certain amount (you pet the animal, lowering the light level), the animal makes sounds and moves. You can change the sensitivity of the photocell (800) to a value between 200 and 1100 depending on ambient light you expect.
The register/interrupt code allows the servo to be refreshed periodically to have it stay where it is commanded to. The Arduino Servo library does not work for Trinket/Gemma so the Adafruit Softservo library is used.
Open up the Arduino library manager
Search for the Adafruit SoftServo library and install it
We also have a great tutorial on Arduino library installation at:
http://learn.adafruit.com/adafruit-all-about-arduino-libraries-install-use
Please ensure your Arduino IDE is version 1.6.7 or above to support Trinket optimally. You can download the Arduino IDE at arduino.cc.
The code below may be copied into a new project window in the Arduino IDE.
// SPDX-FileCopyrightText: 2018 Phillip Burgess/paintyourdragon for Adafruit Industries
//
// SPDX-License-Identifier: MIT
/*******************************************************************
Adafruit Animal - control code for toy animal animation
Required library is the Adafruit_SoftServo library
available at https://github.com/adafruit/Adafruit_SoftServo
The standard Arduino IDE servo library will not work with 8 bit
AVR microcontrollers like Trinket and Gemma due to differences
in available timer hardware and programming. We simply refresh
by piggy-backing on the timer0 millis() counter
Required hardware includes an Adafruit Trinket microcontroller
a servo motor, a piezo speaker, a photocell, and a resistor
As written, this is specifically for the Trinket although it should
be Gemma compatible.
*******************************************************************/
#include <Adafruit_SoftServo.h> // SoftwareServo (works on non PWM pins)
#define SERVO1PIN 0 // Servo control line (orange) on Trinket Pin #0
#define SPEAKER 1 // Piezo Speaker on GPIO #1
#define PHOTOCELL 1 // CdS photocell on GPIO #2 (A1)
Adafruit_SoftServo myServo1; // create servo object
int16_t servoPosition; // servo position
void setup() {
// Set up the interrupt that will refresh the servo for us automagically
OCR0A = 0xAF; // any number is OK
TIMSK |= _BV(OCIE0A); // Turn on the compare interrupt (below!)
servoPosition = 90; // Tell servo to go to midway
myServo1.attach(SERVO1PIN); // Attach the servo to pin 0 on Trinket
myServo1.write(servoPosition); // and move servo
delay(15); // Wait 15ms for the servo to reach the position
pinMode(SPEAKER,OUTPUT); // Set Trinket/Gemma Digital 0 to output
// to drive the piezo buzzer (important)
}
void loop() {
uint16_t light_reading; // value read from photocell voltage divider
if(servoPosition != 0)
servoPosition = 0; // if it's up, go down & visa versa
else
servoPosition = 180;
light_reading = analogRead(PHOTOCELL); // Read Analog pin 1 for the changing
// voltage from the CdS divider
if(light_reading < 800) { // if the photocell is dark enough, we're petting
chirp(); // so make sound ...
myServo1.write(servoPosition); // and tell servo to move
}
delay(1000); // wait a second between checks/chirps/movements (changable)
}
// Generate the Bird Chirp sound
void chirp() {
for(uint8_t i=200; i>180; i--)
playTone(i,9);
}
// Play a tone for a specific duration. value is not frequency to save some
// cpu cycles in avoiding a divide.
void playTone(int16_t tonevalue, int duration) {
for (long i = 0; i < duration * 1000L; i += tonevalue * 2) {
digitalWrite(SPEAKER, HIGH);
delayMicroseconds(tonevalue);
digitalWrite(SPEAKER, LOW);
delayMicroseconds(tonevalue);
}
}
// We'll take advantage of the built in millis() timer that goes off
// to keep track of time, and refresh the servo every 20 milliseconds
// The SIGNAL(TIMER0_COMPA_vect) function is the interrupt that will be
// called by the microcontroller every 2 milliseconds
volatile uint8_t counter = 0;
SIGNAL(TIMER0_COMPA_vect) {
// this gets called every 2 milliseconds
counter += 2;
// every 20 milliseconds, refresh the servos!
if (counter >= 20) {
counter = 0;
myServo1.refresh();
}
}
Page last edited January 22, 2025
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