Category: Arduino EN

Here is an example of a bird’s voice generation using the Arduino Nano microcontroller (ATmega328)

The code is taken from http://120.107.171.121/~tywua/sub/ISAR/Chirp.ino, apparently from a professor’s website at National Changhua University of Education, Taiwan.

Here is an example of the resulting sound:

Here’s the signal form in the Audacity app for 1 set of tweets only:

Here’s the source code (from http://120.107.171.121/~tywua/sub/ISAR/Chirp.ino)

int piezopin = 11;  Select the PIN for the speaker
int angulo = 0;
int counter = 0;


void Setup () {
  pinMode (Piezopin, OUTPUT);
}
void Loop () {
  Angulo = random (10.50);
  Counter = random (2.6);

  highChirp (5, Angulo/10);
  Delay (100);
  lowChirp (Angulo * 4.2);
  Delay (100);
  Tweets (counter, 2);
}

void highChirp (int intensity, int chirpsNumber) {
  I.
  int x;
  for (int veces = 0; veces<=chirpsNumber; veces++){
    for (i = 100; i > 0; I--)
    {
      for (x = 0; x<intensity;  x++)
      {
        digitalWrite (Piezopin, HIGH);
        delayMicroseconds (i);
        digitalWrite (Piezopin, LOW);
        delayMicroseconds (i);
      }
    }
  }
}

void lowChirp (int intensity, int chirpsNumber) {
  I.
  int x;
  for (int veces = 0; veces<=chirpsNumber; veces++){
    for (i = 0; i<200; i++)
    {
      digitalWrite (Piezopin, HIGH);
      delayMicroseconds (i);
      digitalWrite (Piezopin, LOW);
      delayMicroseconds (i);
    } 
    for (i = 90; i > 80; I--)
    {
      for (x = 0; x<5;  x++)
      {
        digitalWrite (Piezopin, HIGH);
        delayMicroseconds (i);
        digitalWrite (Piezopin, LOW);
        delayMicroseconds (i);
      }
    }
  }
}

VOID tweet (int intensity, int chirpsNumber) {

I.
int x;
Normal chirpsNumber 3, normal intensity 5

for (int veces = 0; veces<chirpsNumber; veces++){
  for (int i = 80; i > 0; I--)
  {
   for (int x = 0; x<intensity;  x++)
   {
     digitalWrite (Piezopin, HIGH);
     delayMicroseconds (i);
     digitalWrite (Piezopin, LOW);
     delayMicroseconds (i);
   }
  }
}
Delay (1000);
}

Making flashing LEDS is one of the simplest ways to demonstrate the timing capability of microprocessors.

Here are some techniques you can do:

• Timer interruptions
• Standard Arduino delay
• Delay from FreeRTOS

Standard Arduino Delay

Delay on Arduino explained at https://www.arduino.cc/reference/en/language/functions/time/delay/

On standard Arduino software such as Arduino Nano and UNO, this delay is implemented with the Loop software.

Example of a software using this delay is an example of Blink software on Arduino (https://www.arduino.cc/en/tutorial/blink)

The flow Diagram of the Blink program is as follows

A Delay on FreeRTOS

FreeRTOS allows the Arduino software to have multiple loops at the same time.

Ported FreeRTOS for Arduino UNO and Nano can be viewed at https://github.com/feilipu/Arduino_FreeRTOS_Library

This FreeRTOS Library can be installed on the Arduino IDE from the Tools-> Manage Libraries menu. Then search by keyword FreeRTOS.

For example, here is a flowchart diagram of a program that makes the LEDS blink with 3 loops. Each LED has a different frequency.

The Source code can be viewed at https://github.com/waskita/embedded/tree/master/atmega-blink-freertos

The FreeRTOS function used is

• xTaskCreate to create a new task
• xTaskGetTickCount to get a tick on the OS at a time
• vTaskDelayUntil to create a delay

Here’s the Arduino Nano hardware demo

Timer Interruptions

Under construction