![]() ![]() Increase the single resistor and you effectively decrease the current to the piezo in the ON and OFF cycles. If you are driving your output high AND low, then a series resistor and a 50% duty cycle output charges and discharges the "capacitor" evenly. The piezo can be thought of as a capacitor. Here's a couple links to some code that may help: You can also put this code at the end of your loop() routine to keep it from looping over and over: while(true) //kill loop, while true do nothing You should hear a 2048Hz tone on your buzzer for 3 seconds. 1 / 2048Hz = 488uS, or 244uS high and 244uS low to create 50% duty cycle With this code: for (long i = 0 i < 2048 * 3 i++ ) If you replace this code: digitalWrite(buzzPin, HIGH) Given that you are driving it correctly now, you need to "stimulate" it. This will drop the 12V down to 3.5V for your buzzer, since it has a coil resistance of about 42ohms. 2W would be better, but you are only turning it on for 3 seconds so it shouldn't get too hot in that period of time. It should be obvious by now that you have the kind you need to stimulateīased on your buzzer's specs, I would change your resistor from 470ohms to 100ohms. Some buzzers "self-oscillate" at a particular frequency, and some need to be stimulated at a frequency to produce a sound. There actually is no problem with your code if you had the right buzzer. I assume the other pins you are sending HIGH are turning on some LEDs. */ /* * following cut from How to adjust Arduino PWM frequencies by macegr in this forum post Pins 11 and 3: controlled by timer 2 in phase-correct PWM mode (cycle length = 510) Setting Divisor Frequency 0x01 1 31372.55 0x02 8 3921.16 0x03 32 980.39 0x04 64 490.20 All frequencies are in Hz and assume a 16000000 Hz system clock.Looks like you are trying to make a racing light. This example code is in the public domain. On most Arduino, the PWM pins are identified with a "~" sign, like ~3, ~5, ~6, ~9, ~10 and ~11. ![]() The analogWrite() function uses PWM, so if you want to change the pin you're using, be sure to use another PWM capable pin. * Fade This example shows how to fade an buzzer on pin XX using the analogWrite() function. (Arduino PWM cheat sheet, checked 27/March/2020) Read more If you want to use PWM to drive a standard piezo element I found that maximum volume could be achieved by altering the PWM frequency to one that closely matches the resonant frequency of the piezo element. I had no success in getting this to work. ![]() I tried a variety of PWM frequency’s and altered the step delay to 3 seconds thinking there may be a capacitor that needed charging within the device. I renamed some of the variables for clarity.īuoyed by my success I attempted to control the brightness of a 5 volt flashing LED. I altered the PWM pin and added in code to set the PWM frequency. The ground end of the DC piezo sounder is connected to ground, the positive to PWM pin 11 which provides the drive signal.ĩ9% of the code consists is the Fade sketch which you can find in the Arduino IDE under File->Examples->01.Basics->Fade. The circuit consists of an Arduino UNO and a DC piezo sounder element. I wondered if I could get a less distorted sound by altering the PWM frequency, so using the Arduino PWM frequency cheat sheet I worked my way through the possible pin and frequency combinations eventually settling on the frequency of 31372.55Hz which is available on both pins 9 & 10 (timer1) and 3 & 11 (timer 2) I found this frequency to give the cleanest sound. My initial tests were somewhat discouraging, I found I could alter the sound volume but the tone output seemed distorted. In some circumstances I find the sound level too loud, so experimentally I tried using PWM to see if I could alter the sound level. I quite often use a DC piezo buzzer for the sound element of my circuits I find these buzzers give a much louder sound level than can be obtained simply by using the tone() command to drive a standard piezo element. ![]()
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