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buzzer 3 Pins

Fri Jan 24, 2020 10:07 pm


I tried to make sound with a buzzer with 3 PINS. The code is as below. When I ran it it doesnt sound but... I hear like a click every second. Why I cant hear any sound?

Code: Select all

import RPi.GPIO as GPIO
import time

buzzPin =11

  GPIO.setup(buzzPin, GPIO.OUT)
  while True:
    GPIO.output(buzzPin, GPIO.LOW)
    GPIO.output(buzzPin, GPIO.HIGH)


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Re: buzzer 3 Pins

Fri Jan 24, 2020 10:33 pm

Have you got the buzzer the right way round. They have a polarity. The anode on the buzzer needs to connect to GPIO11 (pin#23)

The cathode of the buzzer needs to connect to a ground pin.
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Re: buzzer 3 Pins

Sat Jan 25, 2020 10:26 am

It might also be useful to post details of your 3-pin buzzer

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Re: buzzer 3 Pins

Sat Jan 25, 2020 1:01 pm

It is this one

See in the attachment how is connected
WhatsApp Image 2020-01-25 at 10.22.48.jpeg
WhatsApp Image 2020-01-25 at 10.22.48.jpeg (180.61 KiB) Viewed 172 times

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Re: buzzer 3 Pins

Sat Jan 25, 2020 1:14 pm

Well the description seems to be a bit confusing as it can't decide if its a buzzer or a sensor
Low Level Trigger Magnetic Passive Buzzer Alarm Sound Sensor Module
So which is it a buzzer or a sound sensor ?

but it claims
5.When the I / O port input high, the buzzer sound
regardless of all that you have your white wire on the wrong pin , you have it on physical pin 11 but you are using BCM numbering so you want it on gpio 11 which is physical pin 23

Code: Select all

buzzPin =11
Last edited by pcmanbob on Sat Jan 25, 2020 6:27 pm, edited 1 time in total.
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Re: buzzer 3 Pins

Sat Jan 25, 2020 5:35 pm

No sensor. In china-talk the word 'passive' denotes speaker transducer only whereas 'active' has built-in tone generator IC. I know this from having purchased thousands of the latter for a client and personally ended up with quite a few speaker type too. No matter what an amazing deal at 3-4 cents ea.

Occasionally there will be bait and switch artists that incorrectly send the cheaper speaker ones. Not too often though and with Ebay Protection you get to keep them for free.

Note that the speaker only type can sort of function as a sound sensor (mic). Just not very good ones compared to piezo or electret.

As usual 'Arduino' PCB modules are a total rip off if you have any DIY capability at all. That transistor is not always needed with modern MCU pin drive. Hence maybe some confusion over Dougie hinting at only two pins which is actually the smarter configuration (IDK about 'cathode' and 'anode' though, lol).

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