I have connected a tiny piezo pc speaker (https://sktechworks.ca/wp-content/uploads/2017/11/Speaker.jpg) to an arduino and used to tone command to play a simple melody in repeat (square wave only since I didn't use a DAC).
But the speaker is very quiet. I have used a speaker like the green one here: enter image description here

but it is not siginifcantly louder (I need a piezo either way). I then tried to just connect it to 2 digital ports and just inverted low and high between them, which did make it louder, just not enough.

So here my question, with the same voltage is there a way to produce a louder sound? I just need a sound can clearly hear through a few walls. Because I have a usb speaker (which is 5V) and that one is signifcantly louder.

  • \$\begingroup\$ What matters is not the speaker/sounder you're using but that the output of the module you take the output from is capable of driving a speaker. If it is not explicitly stated that that output can drive a speaker (for example it is named: SPK+ / SPK-) then probably it cannot drive a speaker, it might be a "line" level output. Then you need an audio power amplifier in between. Something like a module based on the LM386 chip. \$\endgroup\$ Commented Mar 3, 2019 at 11:05
  • \$\begingroup\$ I thought a speakers resitance changed with the one applied to it? Menaing the more amps the louder it gets? \$\endgroup\$ Commented Mar 3, 2019 at 13:38
  • \$\begingroup\$ also don't I need an external powersource for an audio amplifier? \$\endgroup\$ Commented Mar 3, 2019 at 13:40
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    \$\begingroup\$ First, is that actually a piezo and not a magnetic speaker?. Unfortunately Bimpelrekkie's claim is quite incorrect - what you need to drive a small piezo vs a magnetic speaker is quite different. So first you must figure out what you have. Does it have a low resistance when measured out of circuit with a speaker? If so it is magnetic. In contrast a piezo looks like a capacitor and will be seen as an open circuit by an ohm meter. \$\endgroup\$ Commented Mar 3, 2019 at 14:13
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    \$\begingroup\$ @Bimpelrekkie continuous mix up the technical facts. Piezo and magnetic speakers are drastically different loads, and while there are ways in which piezo tweeters can be used in hybrid systems, they are not a natural match - in fact they often require a series resistor. At a basic level, a magnetic speaker looks like a short circuit at DC, while a piezo is an open circuit at DC but looks like a short circuit to fast transitions, which means that it can readily overheat cheaper class D amplifiers. And with a square wave source, there's little reason to use an inefficient linear amplifier. \$\endgroup\$ Commented Mar 3, 2019 at 17:11

1 Answer 1


use an impedance matching transformer with largest turns ratio

such as these

  • \$\begingroup\$ Could you expand this answer? \$\endgroup\$
    – Voltage Spike
    Commented Nov 19, 2021 at 6:39

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