I have a 9v square battery connected to a pezio buzzer and i want to use a potentiometer to vary the tone of the buzzer. So when the potentiometer is at its highest resistence the buzzer does not sound and at its lowest its at full. What im unsure of is what resistance potentiometer i need to get? Any help appreciated.

As an aside, any thoughts on how to vary the volume of the buzzer without changing the tone?

Vary the tone? Or the volume?

I’d reckon that any pot will actually work, it might just be that the useable sweep of it will vary…
But then I don’t actually know about electronics 🙂

I’m pretty sure that the tone will vary from high pitched to a low buzz if i use a pot as the voltage driving the buzzer will be reduced. i have no idea how to vary the volume and keep the same tone! if anyone knows im all ears…

what im lookign for is a pot that will give me a full 270degrees range at the end of which the buzzer will be recieving no voltage from the battery.

Buzzers don’t work like that. If you want tones, you’ll need to supply it with a sine wave input (or a PWM approximation) and even then it probably won’t work.

It’s been a bloody long time since I dabbled with this sort of thing, but I’m fairly sure I remember having a piezo buzzer that was a self-contained unit. You put a voltage across it, and it had all the necessary gubbins to make it sound.

In which case, I suspect that for that sort of buzzer, the tone is fixed. Using a pot to reduce the current flowing through it is just going to make it quieter.

I think.

Yeah, mine looked different, but this sort of thing.

http://www.maplin.co.uk/dc-operated-piezo-buzzer-3217

The traditional buzzer requires a generated square wave according to Maplin (though I’d expect a square wave to buzz and sine to tone, if my GCSE electronics memory is correct)

http://www.maplin.co.uk/piezo-transducers-3202

yep thats the same as i have Cougar, it has the drivers and what ever else built in. My thought was that, as you say, if you use a pot to reduce the current/voltage (?) it will reduce the volume. i wasnt sure of the tone would change or the volume. idealy id like the volume to reduce.

Faperon, you dont think this would work? i know from using 9v down to 1.5v batteries the buzzer does get quieter

Right.

Again, I’m rusty, but I suspect that pretty much any pot value would work; you’ve got fully open at one end and fully closed at the other. I’ve half a memory (from taking a guitar to bits in a past life) that you need a logarithmic pot for a volume control (and linear for tone?), but I may have made that up.

Sorry, I’m trying to be helpful without actually knowing properly what I’m talking about. But then, this is STW. (-:

I don’t really know what I’m talking about either, but that Maplin link shows it works on 5v TTL, which in my understanding is a digital switching signal. So it’s either on or off – reducing the voltage will have no effect until it reaches the point where it goes off.

A) check that the buzzer you have will vary it’s output level with a varrying input voltage (not all do, and it is unlikely to be linear). the easiest way to do this is using a varriable output powersupply.

b) using the rated voltage and current, work out the power consumption of your buzzer. Chances are, unless it is very small it will not be possible to drive it directly with a potentiometer (as the power drop across the pot will be too much) If this is the case you will need to use an additional transistor to drive the buzzer, with the Potentiometer just supplying the base current to the transistor. A NPN transistor set up in this way is called an “emitter follower”, google it for the simple circuit required.