Speaker/sound and volume control

Hi everyone. So I’ve tackled a lot of things regarding my new project, but I haven’t even thought about the speaker and the volume control. I have never done any wiring regarding volume wheels or speakers. So if I remember correctly, the Arduboy uses a Piezo speaker. I was looking at some Piezo speakers and I found this one: https://www.amazon.ca/Gikfun-Speaker-Diameter-Arduino-Speakers/dp/B07BFTYY6L/ref=sr_1_12?dchild=1&keywords=piezo+speaker+component&qid=1632490688&sr=8-12
It says this: “8Ohm 8R 2W”. What does it mean? It says this too: “EK1887C”. What do you think it is? As for the volume wheel, I found this: https://www.amazon.ca/Uxcell-5-Pin-Linear-Potentiometer-16mmx3/dp/B013FPKCMM/ref=sr_1_3?dchild=1&keywords=volume+wheel+component&qid=1632491013&sr=8-3#customerReviews
It says this: “10K Ohm 0.05W 3-Pin”. I also don’t know what it means, and if this volume wheel and speaker will work, how exactly will I wire up everything?
Thanks!

That is not a piezo speaker. It’s a standard voice coil speaker.

Oh. I did some more looking and I couldn’t find any so what about a piezo buzzer? Could it be controlled by a volume wheel?

A passive piezo buzzer is the same as a piezo speaker.

It’s possible to add a potentiometer to control the volume. This has been discussed previously in this forum. I suggest you do some searching.

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I think I figured the potentiometer part, but I have a question: are piezoelectric buzzers/speakers the same as any passive buzzer?

No, there are piezo types and voice coil types.

Are the passive buzzers from the Elegoo uno r3 piezoelectric ones? Because I’m using those. Also, does the potentiometer type like 10k or something matter?

Measure across the leads of the buzzer with your ohmmeter. If it reads between 8 ohms and 32 ohms it’s a voice coil buzzer. If it reads infinite resistance it’s a piezo.

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I tried measuring it with my industrial multimeter (on the resistance setting) but it wouldn’t do anything. I think the multimeter is fine because it worked besides measuring the resistance. Is there any other way?

I can’t find any buzzers associated with elegoo uno r3. But if it’s in the typical buzzer housing (small black plastic drum) just look at the bottom. If the legs are coming from a glob of epoxy, the buzzer has an internal oscillator and is useless here. If it’s just got a PCB with two contacts or pins (- and +) , you should be good. Wire it up and test that it makes sounds properly, then add a small pot between it and one of the arduino pins it had been assigned. Using a pot to control volume like that is dirty but it works, mostly.

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(At least the larger) Elegoo UNO R3 kits come with both a passive and active buzzer. It’s not specified and hard to tell from the manual if the passive one is voice coil or piezo.

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Can you measure a known value resistor with it and get a proper reading? This will tell you if the ohmmeter part of it is working. Or just short the leads when on resistance and see if it goes to (or very close to) zero.

If one or both of the above tests work and you don’t get any reading across the passive buzzer, then it’s probably a piezo.

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I tried it with another multimeter and the resistance I got was in the 1500s. You said it’s voice coil if it was from 9 to 32 but I don’t understand what you meant by “infinite” resistance.

No, it wouldn’t record anything.

yep, that’s what it looks like.

If the legs are coming out of epox/resin, it’s an active buzzer and useless for the arduboy as a speaker.

By “infinite” I meant very, very high. So high that it’s higher than the meter’s measuring range, so it shows the same as when the meter’s leads are open and not connected to anything.

It’s easy to test for an active buzzer. Just put 5V across it. If it plays a tone continuously, it’s an active buzzer. Make sure you put the 5V on the lead marked with a + sign and ground on the other lead.

It’s best to try this for no more than a second because if it’s a passive voice coil buzzer you could overheat it and burn it out.

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According to the Elegoo manual:

Buzzers can be categorized as active and passive ones. Turn the pins of two buzzers face up. The one with a green circuit board is a passive buzzer, while the other enclosed with a black tape is an active one.

That still doesn’t tell us whether the passive one is voice coil or piezo.

Based on the fact that the Elegoo manual shows the passive buzzer connected directly between a pin and ground, and also from the schematic symbol used, I’d say it’s probably a piezo buzzer.

elgoo_passive_buzzer

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