Buzzer - How to Use Buzzer

Tutorial Video

Hardware

• PHPoC Blue or PHPoC Black
• Micro USB to USB Cable (to upload source code to PHPoC Device)
• Piezo Buzzer
• Jumper wires

About Buzzer

Buzzer is used to make sound, tone and alerts. The buzzer used in this example includes three pins:

• VCC pin.
• GND pin.
• Signal pin (receives the control signal from controller).

How the buzzer works:

• If generating a square wave of the specified frequency (and 50% duty cycle) on signal pin of buzzer, buzzer makes a specific tone corresponding to the frequency.
• If controlling the signal pin of buzzer to HIGH (3.3V to 5V), of buzzer makes constant sound.
• If controlling the signal pin of buzzer to LOW (0V), of buzzer keeps silent.

How to control buzzer:

• This example shows how to simply control buzzer by controlling the signal pin of buzzer to HIGH or LOW to generate sound or mute, respectively. To do so, It just needs to connect an digital output pin of PHPoC devices to the signal pin of buzzer and control it. For advanced control, use can use hardware/software timer to generate a square wave of the desired frequency.

We can use another kind of buzzer instead, even if it has different pinout, for example:

• Grove buzzer (for more convenience, use it in combination with PHPoC Grove Expansion Board).
• Piezo buzzer

We can use the source code of this example if its working principle is the same as the buzzer used in this example.




Wiring Diagram



Quick Steps

Source code of this example is a part of PHPoC Support Packet (PSP). You need to:

• Download PHPoC Support Package.
• Upload example\p4s\01.php_task\01.uio_buzzer to PHPoC Blue/Black.
• Click "Run" button on PHPoC Debugger.

If you use PHPoC for the first time, see How To Use PSP.


Source Code

Source files includes:

• init.php: this file is run when PHPoC system is powered or reset. It is used to specify which file is run is system loop.
• task0.php: this file is run in system loop of PHPoC devices.

init.php

This file is run when PHPoC system is powered or reset. It is used to specify that task0.php is run is system loop.

<?php

system("php task0.php");

?>

task0.php

[Full Code]

<?php

if(_SERVER("REQUEST_METHOD"))
 exit; // avoid php execution via http request

include_once "/lib/sd_340.php";

define("OUT_PIN", 0);

echo "PHPoC example : P4S-34X / UIO / Catalex Buzzer\r\n";

uio_setup(0, OUT_PIN, "out low");

while(1)
{
 uio_out(0, OUT_PIN, HIGH);
 usleep(100000);

 uio_out(0, OUT_PIN, LOW);
 usleep(900000);
}

?>

[Explanation]

Source code of this file does:

• Setup IO pin to output mode and initialize IO pin state to LOW (Buzzer is mute).

In infinite loop:

• Tongle output pin between LOW and HIGH to turn ON/OFF Buzzer.

See Also

• Buzzer - Controlling Buzzer from Webpage using Hypertext.
• Buzzer - Controlling Buzzer from Webpage with Image.
• Buzzer - Controlling Buzzer via WebSocket.

Other Resources

• PHPoC System Files
• How PHPoC System Works
• How To Use PHPoC Support Package