how to increase the buzzer loudness

RE: how to increase the buzzer loudness

Ole Bauck — Tue, 15 Dec 2015 10:25:40 GMT

Same question as this post: https://devzone.nordicsemi.com/question/54947/how-to-configure-buzzer-in-nrf51-evb/?answer=54985#post-id-54985

RE: how to increase the buzzer loudness

MARTIN FR — Fri, 11 Dec 2015 15:59:17 GMT

thank you so much for your reply but after flashing the program my pwm pin which i configured as gpio it is showing 2.9V but i want them to show set as output after pressing the button and i ahve managed both the button and pwm beep sound only problem is i want to set the pwm pin as output after press the button

RE: how to increase the buzzer loudness

Ole Bauck — Fri, 11 Dec 2015 15:44:43 GMT

Output is low impedance, input is high impedance. See this post for handling button pushes, add pin set or clear inside button event handler depending on if the button was pushed or released (button action).

RE: how to increase the buzzer loudness

MARTIN FR — Thu, 10 Dec 2015 10:10:51 GMT

can you please tell me how can i make the pin 6 and pin 7 as output(high impedance state )only during the button press event and it has to be connected to low impedance state (GND ) except the button press event

RE: how to increase the buzzer loudness

Ole Bauck — Wed, 09 Dec 2015 16:56:18 GMT

Is this the peak to peak voltage of the PWM or the average voltage. You are running the PWM at 50% (?) which will make the average voltage half of Vcc (2.9V*0.5).

RE: how to increase the buzzer loudness

MARTIN FR — Wed, 09 Dec 2015 16:15:24 GMT

i have configured the gpio pins in high drive mode NRF_GPIO->PIN_CNF[7] = (GPIO_PIN_CNF_DRIVE_H0H1 << GPIO_PIN_CNF_DRIVE_Pos);

after compilation i measure the voltgae on the gpio pin it is showing 2.9V but during the beep sound produced from the buzzer the voltage drops to 1.5 v alomost half of the voltage getting dropped i dont know why ? is it buzzer consuming too much current or my GPIO configuration is not configured properly to gpio high drive mode 5mA can you please tell me some suggestions how toa void the voltage drop?

i have attached my program in the main post please verify it and let me know some modifications

RE: how to increase the buzzer loudness

Ole Bauck — Thu, 03 Dec 2015 16:33:05 GMT

Looks like the impedance is 1Kohm. If this is correct, the current draw will be 3.3mA if Vio is 3.3V, which is within spec. It also seems like the buzzer will beep at 9KHz if DC is applied to it, if so you dont need PWM, just set the gpio high. To get higher loudness you will need higher voltage. I am not an expert at buzzers, but this is what I understand from the buzzer specification.

Regarding using the negative of the buzzer as an antenna, I have never heard of this and it does not sound like a good idea. What is the background for doing this?

RE: how to increase the buzzer loudness

MARTIN FR — Thu, 03 Dec 2015 16:08:33 GMT

I am using 7BB-12-9 yes i just connected pin 6 and 7 together in PCB but can you verify my code because i would like to do this function press the button for three seconds then only the buzzer has to beep am not able to interface the PWM function along with the buzzer function

RE: how to increase the buzzer loudness

Ole Bauck — Thu, 03 Dec 2015 15:41:40 GMT

If the pins are not perfectly in sync you will risk a short circuit. The maximum current recommended from each pin is 5 mA. Can you specify what kind of buzzer/antenna you have?

RE: how to increase the buzzer loudness

MARTIN FR — Thu, 03 Dec 2015 14:33:09 GMT

Non i cannot use transistor because am usinng negative terminal of the buzzzer conencted to antenna so i want to use these two pins 6 and 7connected together to buzzer positive terminal so the maximum current of one gpio pins 5mA so the buzzer positive terminal wiill receive maximum upto 10mA in that way i can able to increase the sound of the buzzer

note: i think inside the nordic chip iteslf there is a transistor right?

please let me know if i am wrong in my concept

RE: how to increase the buzzer loudness

Ole Bauck — Thu, 03 Dec 2015 14:29:28 GMT

They will be output so not high impedance. You should be fine with a transistor.

RE: how to increase the buzzer loudness

MARTIN FR — Thu, 26 Nov 2015 14:43:11 GMT

i mean pin 6 and pin 7 are connected together to the Buzzer , so it will be always in an high impedance state is it correct? or i am using the transistor then no need of connection two pins to the buzzer right?

RE: how to increase the buzzer loudness

Ole Bauck — Thu, 26 Nov 2015 14:38:17 GMT

Transistor: Probably good. 1: I would not recommend connecting two pins together because you may by accident short circuit Vio (if one pin is high while the other is low). 2: Negative terminal of buzzer as antenna? You need a dedicated antenna or PCB trace, with a matching network. See the reference layouts and the hardware files for our boards, like the DK kit.

RE: how to increase the buzzer loudness

MARTIN FR — Thu, 26 Nov 2015 13:31:02 GMT

Thank you for your suggestion PMBT2222A i have choosed this transistor can you tell me whehter it is a good one moreover i would like to confirm this point with you

1)i configured pin6 ,pin 7 in series and connected to positive of the Buzzer pin for PWM so that the buzzer will get higher current then there is a possibility of makeing more sound whether it is good option or not a prefered one please let me know about this point 2) i am also using the negative terminal of the buzzer like antenna so i have to make sure there wont be any conflict for RF performance can you please give me some idea about this point

RE: how to increase the buzzer loudness

Ole Bauck — Thu, 26 Nov 2015 12:39:37 GMT

A transistor can be very small, like the SOT-23 package. If the buzzer draws too much current from the gpio pin, the voltage will drop and so will the sound level. You can configure the gpio for high drive with this code:

NRF_GPIO->PIN_CNF[PWM_PIN] |= (GPIO_PIN_CNF_DRIVE_H0H1 << GPIO_PIN_CNF_DRIVE_Pos);

You should also rather sink current than source current, see here. This means the connection will be: VCC->BUZZER->GPIO

RE: how to increase the buzzer loudness

MARTIN FR — Thu, 26 Nov 2015 12:02:05 GMT

yes its a good option for me to test but i am looking for some smaller dimension component because my PCB is very small so i cannot able to affors that much big transistpr

RE: how to increase the buzzer loudness

Ole Bauck — Thu, 26 Nov 2015 11:32:29 GMT

Use a transistor, see here.

RE: how to increase the buzzer loudness

MARTIN FR — Thu, 26 Nov 2015 10:49:37 GMT

yes i have modified the duty cycle but am still getting little audible sound only for example i want to make the buzzer beep which can audible upto 30meters approx so inorder to create that kind of loudness what i must to do can yout ell me how can i change the supply voltage inorder increase thze sound

RE: how to increase the buzzer loudness

Ole Bauck — Wed, 25 Nov 2015 13:16:33 GMT

You can increase the duty cycle (which will increase the average voltage), or you can increase the supply voltage. Do what is easiest for you. The average voltage will determine the loudness: loudness = supply voltage * duty cycle.