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A & #!$%ing Button is a good project that can save lives!
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By: Mehdi Sadaghdar
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0:00 Intro and Sponsor
2:00 Making the Acoustic Chamber
8:34 Designing the Speaker Driver

Hi today, i'd like to make a button: yes, a button with this button. Whenever you want to you just press the button and you i know for a fact that a lot of people prefer rather than well not you know. Sometimes, in the heat of the moment, you feel passionate and just want to do it, but if you are quick, you can stop yourself and instead press the button it could save your career thing is basically a will you please stop censoring my words. Thank you.

Stop it i'm just saying bleep a bleeping button. Basically, i want to make a button that when you press it makes a bleeping sound, which is like a one kilohertz sine wave like what is it good for i was thinking during live streams or conversations or meetings. Even when you feel angry and want to swear, you can just convey your feelings by pressing the bleeping button like holy you'll, get it off your chest and feel good. Everyone knows what you mean, but you don't have to actually swear and people can use their imagination to feel the bleep with whatever word they want.

What, if in their heads, they fill the blank with something very offensive, and you end up getting cancelled for a bleeping. Sound well, let me know how it will work for you now. You might think what a boring project just a button that makes a sound, oh yeah, then why don't you go to my sponsor curiosity stream and watch a documentary instead seriously? Curiosity stream is a subscription streaming service that offers thousands of superb documentaries and non-fiction titles, including exclusive originals, from some of the world's best filmmakers. Excluding me, i guess, and through curiositystream.com electroboom, you get 25 percent of your unlimited access to this treasure box for only 14.99.

A year that's around what other services charge monthly so use it. Now, let's make the button anyway, to make this a lot of people just whip out an arduino board or something and program it to output, the signal they need, which can be quite beneficial, because you have the flexibility to change the shape and frequency. We are not. Here to do software, what you write some code and suddenly you know, electronics, you don't know a damn thing and i still don't know how to program arduino.

So we do electronics. This is where my stash of broken junk becomes handy, because in there i can find a headset out of which i can harvest a speaker. Here's the speaker, the headset speakers, don't output, much audio though they are not made to yell. But let's see i connected it to my function, generator at one volt amplitude, which is the maximum.

These guys should take, and it sounds weak like when you stub your toe. But the main reason for the weakness is that this speaker doesn't have an acoustic chamber, as is an acoustic chamber. If i'm calling it right is basically a cavity in front of the speaker with some holes that the sound comes out of all audio products must have it, as they say. What an acoustic chamber does is that it provides some impedance matching, which is basically helping to pair the very hard surface of the speaker diaphragm to the very soft surrounding air.

The chamber creates an acoustic pressure in front of the speaker that provides a more gradual transition between hard to soft and maximizes the energy transfer. But every acoustic chamber has a specific resonance frequency, just search for helmholtz resonance to understand it better, but basically the resonance frequency of the chamber is dependent on the volume of its cavity and the area of its opening. Among other things, we naturally use this by adjusting our mouth cavity and its opening like adjusting the chamber resonance to the frequency we want to output maximizes its volume, see my little speaker if i put my hand around it. Well, the audio is already louder, but if i make the hole smaller, it rises to a peak and if i go any further, it becomes smaller only at a certain hole size.

I get the maximum volume, which is where the resonance of the cavity is matching. My speaker, frequency, let's see if i can plot some sort of frequency response. For my speaker, i put a condenser microphone in front of my speaker that i have to bias externally. I sweep frequencies from the function generator over the speaker.

The microphone picks it up and scope will plot it. Of course, it's just for reference. Nothing is calibrated here. There we go there, and this is what i hear too weak low frequency response.

The audio level rises with frequency, but above 10k the level just drops again. So, let's make a chamber for the speaker: i'm going to use a drug bottle for my chamber, because it's rigid and won't vibrate with air, and in hindsight i should have called it. A medicine bottle, maybe make it prettier by putting some electric tape on it there. The sound can still come from the back of the speaker, which is typically inside a device that has its own cavity.

So maybe i use the medicine bottle cap to cover behind it too oops. I think i put a ton of air pressure in there release the air pressure cover the hole again good, very little sound is coming out of it. Now we drill a hole in there. Did it make much of a difference? Let's do a frequency response not much at all.

We need more holes, damn it. I just cracked the whole thing: let's see the frequency response of this look at this. Our misfortune actually created a lucky bump at around one kilohertz that we needed just listen to it. Pretty loud eh well to test a bit more, i covered more than half of the hole with some flexible electric tape and see it pushed the peak down at one kilohertz and send it further towards lower frequency.

Maybe a bit larger hole helps a little bit better. Yeah, i just cut the opening a little bit wider, like this look at the massive peak at one kilohertz, and it seems we have some peaks at the harmonics too, which is fine. Our speaker, volume without the chamber, was more like this, and now it's like this and, of course now we can make it even louder by increasing the voltage amplitude. Such high voltages would typically be above the rating of the speaker and could damage it if applied continuously.

But in my application i only momentarily use it see. For example, here i have a 12 ohm half a watt resistor and i'm gon na put 12 volt across it, which means 12 watts of power 24 times the rating of the resistor. But if i do it momentarily, the current reading is off actually pick see. The resistor is still alive, but if i do it continuously, that's when the resistor gets damaged.

So as long as we do it momentarily, we should be fine here in my application. I want the chamber resonance to match my sound frequency, because i want the maximum level, but in typical voice and music speakers. They push this resonance frequency outside the audible frequency band by reducing the chamber volume and increasing the hole size. This is because we typically want a flat response, not a bulge erected in the middle of our pant band.

Now it's time to drive this circuit, i'm going to put a simple circuit together and then i'll explain it damn it. I guess it will grow back and it's done. It runs on two double a batteries with switch and everything and works perfectly. The circuit is quite simple: if you are an electrical engineer, so the circuit is powered by two double a batteries through the switch and capacitor.

Of course, there is no reverse polarity protection, so we better not plug in the batteries backwards, and then we have a schmitt trigger oscillator circuit that creates a square wave here and a triangular wave there, and we take the triangular wave because it's much easier to filter Into a sine wave, we use a simple low-pass rc filter to turn the triangular wave into a sine wave, which also drops its amplitude. So we need a game stage to bring the signal level back up and feed it into the speaker and here's the list of component values. If you care to know here's the square waveform of the schmitt trigger and the triangularish waveform, that is filtered into a sine-way-wish waveform that is amplified, and i can also use a foot switch to keep my hands free when i'm swearing, good man, okay, let's try it Once someone told me you'll wake them up tomorrow, get your together and finish what you started or i'll slap the out of you, and i told him who you think you are trying to dictate my life, and he said i am you. It works see there.

You thought it was a simple project and yet you learned a ton from it and you'll learn a ton more. If you visit my sponsored curiosity stream, i especially found this documentary on the history of electricity quite interesting. It shows those primitive awesome experiments. We don't do much anymore and really brings me back to the roots of electricity and gives me some good video ideas too.

And, of course, curiosity stream is the home to thousands of very well made documentaries and non-fiction titles from science, nature, history, technology, society and lifestyle, and it is available worldwide on many different platforms like web app. Google android xbox one smart tv, ios, chromecast, amazon, fire amazon. Kindle apple tv, i mean only 14.99 for a whole year of some of the best knowledge and science documentaries out. There is an absolute steal so make sure to follow my link, curiositystream.com electro boom and make use of this promotion, and thank you for to watching.


8 thoughts on “Making a &#!$%ing Button”
  1. Avataaar/Circle Created with python_avatars blacktomcat says:

    ooooo. hearing the magic flute, aria of the queen of the night….in a electroboom video was…..suprising XD if anyone told me about that, i'd thought he made the sound with an tesla coil, but him actually singing it? damn^^ thumbs up^^

  2. Avataaar/Circle Created with python_avatars Beau Remington says:

    Mehdi! Don't break your junk, man. Impedance is fine, impotence is not. Health will always come first!

  3. Avataaar/Circle Created with python_avatars Emulated Excitement (Kanawha County WX) says:

    Anybody else notice that the final buttons frequency is a bit above 1 kHz? It's more towards the spectrum of 1.05.

  4. Avataaar/Circle Created with python_avatars zmeister says:

    we know we've had good social progress when science channels are dropping sick cancel culture bars, and not even in a shitty condescending way. love it

  5. Avataaar/Circle Created with python_avatars Nezzero says:

    The subtilty of how you cover your mouth perfectly every time you say beep is pretty impressive haha

  6. Avataaar/Circle Created with python_avatars Stinkcat says:

    Plot twist : &#!$%ing means Bleeping it has 5 words before "ing" and fu#$ has 4.

  7. Avataaar/Circle Created with python_avatars Jan Kołodziej says:

    As a musician, I found your explanation of resonance chamber to be the most bizzaire and weird I have ever heard :D.

    You also surprised me saying that it has to be in front of the speaker. Pretty much every application I can think of has the resonance chamber behind the source of sound, not in front of it. I mean, speaker columns for example have cavity inside, which acts as a resonance chamber, while the speakers are on the outside. Piano has a resonance chamber below the strings, while the opening is over them, same with violin, guitar and many more instruments.

    BTW, a great example of how powerful resonance chamber can be is if you have one of those little instruments used inside music box. Take it out and you can barely hear any sound. Put it on a piano (or even some regular furniture) and suddenly it gets very loud.

  8. Avataaar/Circle Created with python_avatars Rafael Aurelio says:

    ElectroBOOM, can you make a DIY digital Keyboard/synthesizer using the contraption you used in this video?

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