DIY Ultrasonic Audio Laser (Directional Speaker)

Build your own ultrasonic audio laser, otherwise known as an ultrasonic parametric speaker that lets you beam sound to distant places like a laser beam. Total cost is under $20!

Parts List:
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Code and schematics:
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0:00 - 0:56 Intro
0:57 - 2:51 History
2:52 - 5:05 Implementation
5:06 - 10:26 Part Details
10:27 - 10:57 Circuit
10:58 - 12:57 Usage
12:59 - 13:53 Conclusion

#parametricspeaker #ultrasound #audiolaser

[jtjames]

I'm making one of these for my Curse of Strahd D&D game, so I can literally make players hear voices in their heads.

[Tony-nbvt]

They really need to implement this on phones, this would be a practical use, so only the user can hear the audio and not disturbing those around them

[johnioannou]

As a Electronics Engineer I have built many circuits in the past but this is the first time I have a built a ultrasonic Audio laser. I had a bit of trouble to get it to work using the Mic4427 driver chip so I used the L293DNE driver chip instead which has a much higher working voltage of 36v compared to 18v of the MIC4427 and the circuit works fine now I also replaced the preamplifier chip with the TL082 which is capable of operating of a split rail voltage supply. In the future I might use the raspberry pi pico which run at 100Mhz to upgrade the power and sound quality of the Ultrasonic audio laser further.

[spunbearing]

I need one. I got a neighbor who is obsessed with leaf collection to the point he runs his leaf collection trailer on his rider mower (wannabe parking lot sweeper) at full throttle with no muffler all day. I’m certain that he will hate a recording of it directed at his bedroom at 3AM. Gimme.

[nate]

now convince your family there is a ghost in the house

[notthesamagain]

I thought this could be done by people without previous electric/mechanics knowledge and that would have a hands on step by step after the explanation.
Still congratulations, I'll keep searching for a "DIY audio laser for dummies".

[MisterKaen]

I have some crackheads across the street that keep me up more times than not.
I am absolutely going to use this.
Didn't coca cola pay to have this developed because they wanted people to hear a glass of coke being poured when they walked past a vending machine

[allenhuffman]

Thanks for this. I’ve been checking in on directional sound every few years and this looks like something I’ll try to build.

[wizardOfRobots]

Dude...this is very cool.... I got this idea and tried implementing it. Didn't get very far. I thought it could be made like a personal "wireless" earphones device. Like you could be sitting in class pretending to listen to your prof, but actually be listening to songs or whatever. Great job anyway.

[mijnsmt]

You can also generate a PWM-modulated signal by feeding the audio and a 40-kHz sawtooth to a comparator like the LM358

[keithfulkerson]

If you played a mosquito buzzing sound through it, you could make people flail at your command.

[bschwand]

Really great project. Some comments:
this MCU is plenty fast for high quality sounds, it just needs to be programmed right. Arduino is crap for performance.
STM32 uC have tons of timer modes, it could be used much more efficiently.
Also the ADC, your code uses DMA but for one sample... so the interrupt rate is high. Would be much better to use DMA ADC to fetch a few KB samples at a time, then compute the expected response PWM required in a buffer and use another timer to schedule appropriate output frequency changes at the correct rate.
All I am saying is that the code is way sub-optimal and could show much more improvement before anything hardware needs tweaking.

[rodgerrodger]

Just spent a little over $20 to start this project. I got 20 transducers and some higher quality amplifiers, and ive already got a raspberry pi 3 which has a faster clock than the stm32f103.

Im excited to get started on this project!

[Tkillaahh]

That's freaking cool. I bet i could prank people so funny with that. Great work!

[dhebert]

Really great video. Thanks for sharing. I'm just trying to increase my knowledge base in electronics. I'd like to be able to build various electronic devices to use around the house and garage. I can't get over how inexpensive electronics parts are. The electricity part of it was easier for me because, believe it or not, there's alot of parallels to pipe-fitting and hydronics, which was my trade. I'm subbing for sure bud. Thanks again.

[themod]

Thanks for the fun project. It was quite painful to find the proper stm32adc lib, but eventually it worked. Maybe I messed something up in the soldering, but the sound is quiet, directionality is somewhat present but it's more of a bad speaker with noisy audio than an audio laser. At 18volts tc4427 overheats really quickly, so I had to wind down it a bit to have at least several minutes of working time. Probably I'll look for different components and try building v2 when I have some spare time.

[RavenLuni]

Interesting. I imagine using a pure class D amplifier would eliminate any quantisation errors and improve the quality greatly. All you need is a sawtooth generator and a comparator to drive your output stage.

[harrisonschwartz]

Gene, you should try to make a standing wave levitation device using this. You’ll get many views 😂

[MoizCOUK]

I need to build something like this to scare a big colony of tree hanging bats

[IBoughtItMyself]

This channel is one of YouTube‘s hidden gems. Your work is incredible. Although I hate you because you are good looking but also very smart in multiple areas.