Arduino Forum

Using Arduino => General Electronics => Topic started by: allinonemovie on Jun 16, 2018, 10:24 pm

Title: Piezo Buzzer quieter using external power than using usb (both 5V)?
Post by: allinonemovie on Jun 16, 2018, 10:24 pm
I have the following circuit:
(https://i.imgur.com/63ggbVq.png)
When I power the arduino using the USB-Port, everything works as expected. If I use the VIN- and Ground-Pin however (using 5V as well), the Piezo Buzzer is much quieter. Does anybody know why? Electronics noob here :D
Title: Re: Piezo Buzzer quieter with external power?
Post by: Coding Badly on Jun 16, 2018, 10:37 pm

Are you applying 5V to VIN / GND?

Title: Re: Piezo Buzzer quieter with external power?
Post by: allinonemovie on Jun 16, 2018, 10:39 pm
Quote
using 5V as well
Title: Re: Piezo Buzzer quieter with external power?
Post by: Coding Badly on Jun 16, 2018, 10:48 pm

It would have taken less effort to directly answer my question politely asking for clarification.  If you can't be bothered to type "yes" or "no" then I can't be bothered to help you.

Good luck with your project.

Title: Re: Piezo Buzzer quieter with external power?
Post by: allinonemovie on Jun 16, 2018, 10:56 pm
Sorry if that was unfriendly, it wasn't meant like that. I just thought if someone skims through this post, a quote highlights it once again (because you can easily miss it in the post, just like you did).

To make it even more clear, I added it to the title as well.
Title: Re: Piezo Buzzer quieter using external power than using usb (both 5V)?
Post by: Coding Badly on Jun 16, 2018, 11:08 pm

I apologize for the misunderstanding.

Do you have a volt meter / multimeter?

Title: Re: Piezo Buzzer quieter using external power than using usb (both 5V)?
Post by: allinonemovie on Jun 16, 2018, 11:14 pm
Yes, I measured GND against VIN to be approximatily 5V in both cases. The current of the power supply isn't limited and the voltage doesn't drop. It's hard to measure the voltage between D7 and ground when audio is playing, because it's changing so quickly, that my multimeter isn't able to give decent results. Sadly I don't have an oscilloscope
Title: Re: Piezo Buzzer quieter using external power than using usb (both 5V)?
Post by: Coding Badly on Jun 16, 2018, 11:25 pm

Measure VCC to GND while powering through VIN.

Title: Re: Piezo Buzzer quieter using external power than using usb (both 5V)?
Post by: PieterP on Jun 17, 2018, 12:44 am
Vin goes through an LDO, the minimum recommended voltage is usually between 6 and 7V. If you have clean, regulated 5V DC, you can feed it into the 5V pin.

Pieter
Title: Re: Piezo Buzzer quieter using external power than using usb (both 5V)?
Post by: TomGeorge on Jun 17, 2018, 07:40 am
Vin goes through an LDO, the minimum recommended voltage is usually between 6 and 7V. If you have clean, regulated 5V DC, you can feed it into the 5V pin.

Pieter
Exactly, Vin is before the 5V linear regulator, it needs 7V or more on Vin to give regulated 5V supply.


Tom... :) 
Title: Re: Piezo Buzzer quieter using external power than using usb (both 5V)?
Post by: allinonemovie on Jun 18, 2018, 10:19 pm
Thank you! That explains the issue. Interestingly the issue disappeared after soldering, so it seems that there was another problem, but luckily sometimes issues fix themselfs :D But that's good to know for future projects!