alt.hn

1/23/2026 at 5:34:35 AM

I built a light that reacts to radio waves [video]

 https://www.youtube.com/watch?v=moBCOEiqiPs

by codetheweb

1/23/2026 at 10:49:44 AM

Creator here, thanks for posting. And feel free to ask me anything!

by tzvc

1/23/2026 at 10:52:58 AM

I love your works, what kind of background do you have?

by xtoilette

1/23/2026 at 10:55:46 AM

CS background, but I've always been a "bricoleur" on the side

by tzvc

1/23/2026 at 11:05:12 PM

I actually got your video recommended by Youtube earlier today! Glad my YT algorithm is on point.

But would it be possible to add an RSS feed to your blog please? (https://rootkid.me/works) That way I won't miss any of your future posts.

by resurge

1/23/2026 at 3:24:42 PM

How much did that sheet metal frame cost you from PCBWay? Thanks for sharing.

by proee

1/23/2026 at 5:27:55 PM

Around $200 delivered to france

by tzvc

1/23/2026 at 11:54:34 AM

Do you have a list you would be willing to share of trusted manufacturers & suppliers that you reference for different products or materials?

by cheschire

1/23/2026 at 2:43:37 PM

I used JLCPCB for the pcb cause they integrate well with the pcb design software i use (kicad or easypcb)

And I used pcbway for the sheet metal fabrication

Honestly they are both great and similarly priced

by tzvc

1/23/2026 at 12:58:13 PM

At least in the last video it seems like he used both PCBWay and JLCPCB for manufacturing

by flexagoon

1/23/2026 at 1:38:09 PM

Yep! The choice of JLCPCB after having used PCBWay is what inspired the question.

by cheschire

1/23/2026 at 8:46:58 PM

Very cool project. Thank you for sharing. It's rare where something so technical can have such an artistic manifestation. Well done.

by thinkingtoilet

1/23/2026 at 6:44:34 PM

Awesome project & video, thanks for making it

Where did you learn all the PCB design stuff to make your circuit boards that controlled the filaments?

by djhworld

1/23/2026 at 2:53:53 PM

amazing project ! well done ! inspiring to see it this morning the youtube algo recommended it for me. I was thinking what would be a budget way of creating this ? maybe a $20 SDR instead of the hack rf , seems to be a waste of the hack rf to use it as a lamp :)) I think the way you did must have cost you over $1k. Thanks for the inspiration !

by jenowigner

1/23/2026 at 3:47:19 PM

Hackrf is defo overkill for this. I got it cause my initial plan was to cover the whole spectrum

You could probably do it with a cheaper SDR, but it would be slower

Total budget for this is around $1k

by tzvc

1/23/2026 at 2:58:35 PM

IIRC, a regular SDR dongle will not be able to process the full bandwidth of GHZ range.

by orbsa

1/23/2026 at 7:10:29 PM

I do think most people implementing something like this, especially in the exact way this one was implemented would really just be interested in the Wi-Fi ranges.

When I was doing wireless stuff we'd show customers the output of RF analysers to show that even with their wifi turned off their spectrum was packed full of noise.

Having a large viceral display of this would quickly enlighten them.

by pixl97

1/23/2026 at 4:32:52 PM

The $5 nrf52840 should be sufficient, it can scan 114 channels (from 2400-2514 MHz) several times per second, measuring the approximate RSSI.

by 1e1a

1/23/2026 at 8:35:03 PM

You could not use that as an SDR to make a waterfall which is required in this case

by bethekidyouwant

1/24/2026 at 10:16:39 AM

You do not need a full SDR to make a waterfall. The nrf52840 can function as a coarse spectrum analyzer, because it lets you tune to any frequency within its range, and then measure the approximate received signal strength over a period of time[0]. I have tested this myself, and it works pretty well. The only downside compared to an SDR is that it can only listen to one frequency at a time, so it will sometimes miss short signals.

[0] https://docs.nordicsemi.com/bundle/ps_nrf52840/page/radio.ht...

by 1e1a

1/24/2026 at 5:26:28 PM

I know it can switch frequencies, but I predict it wouldn’t make a very pleasing visualization if the updates are slow, but maybe you are right it would look fine for this implementation which is already far off from a waterfall

by bethekidyouwant

1/23/2026 at 5:52:35 PM

HackRF isn't a good SDR by any metric except for the date it came out.

by direwolf20

1/23/2026 at 6:53:55 PM

What would a better alternative be?

by ipdashc

1/23/2026 at 11:43:12 AM

Love your channel! Do you have any plans to eventually open source your projects? (Both in terms of hardware and software)

by flexagoon

1/23/2026 at 2:40:40 PM

To be honest, all of the hardware and software is really poorly documented. But I guess i coudl still publish it as is

by tzvc

1/23/2026 at 7:46:57 PM

Yes, would be still great! I'm sure a lot of people would have fun playing around with it even without the documentation

by flexagoon

1/23/2026 at 11:50:54 AM

I'm personally especially interested in 'Latent Reflection'. I've tried to make something similar never got to a point where I was happy with the output the AI model gave me.

by mechazawa

1/23/2026 at 2:41:58 PM

Lots of tuning to get the model to not immediatly spiral into nonsense. But small models are getting better by the minute, maybe i'll revisit it with a better model and share all the code

by tzvc

1/30/2026 at 11:00:07 AM

That'd be really appreciated. For me it just kept repeating the same phrase or just started reflecting on the prompt itself for a sentence or two after which it started spouting random nonsense like a pasta recipe.

by mechazawa

1/23/2026 at 3:39:09 PM

You’re very good, I’m jealous of your work

by dangoodmanUT

1/24/2026 at 4:40:04 AM

Nice art and a good way of story telling. Thanks for your work!

by me_vinayakakv

1/23/2026 at 9:50:05 AM

Cool project. I was going to say, the end resulting light should be a pretty saturated spectrum, given that many RF sources just keep pumping out waves, and the those waves propagating and bouncing around.

I think one fun application would be a light which represents your wi-fi strength around the house. Obviously in a smaller apartment that's really not a problem, but in larger houses it would be fun to see.

Another application would be to find hidden RF sources / leaks. I have a home recording studio, and for the life I could not find some RF source that kept adding noise / interference. I could roughly detect the frequency of the noise, but not its origin. I guess if I had a couple of RF sensors I could try to triangulate my way to it.

by TrackerFF

1/23/2026 at 10:54:57 AM

Yes, in the parisian apt. where I filmed the RF landscape is wild

But tuning in to the specific wifi channel you router use you could even use this piece as a signal strenght plotter!

by tzvc

1/23/2026 at 7:16:57 PM

>use this piece as a signal strenght plotter

Seems like it wouldn't be hard to filter this for something like the 2.4 or 5GHz range then put a different color filament at the demarcation point for each of the channels.

by pixl97

1/23/2026 at 11:32:09 AM

That’s what I was thinking, the project should yield a few different useful tools. That was a great video.

by ricardonunez

1/23/2026 at 12:24:46 PM

Cool project. Here's some OT: where do people learn to make these videos? Fast paced but calm narration with chill music and sped up action mixed with regular speed. It's a matter of consuming a lot of this content until the form clicks, or you need to go to influ-school?

by kh_hk

1/23/2026 at 2:47:35 PM

No influencer school, no video experience whatsoever actually

I watched TONs of youtube videos growing up and I guess I took inspiration from what I liked in each: fast pace, always shows what you are talking about on screen (no talking head), include tiny projects in the main one, explain the science, use an intro to captivate and an outro to nail the point, use music to drive rythme

I film and record audio with just my phone

by tzvc

1/23/2026 at 3:12:04 PM

Thanks! That kind of makes sense. It's always interesting to me when I see patterns that make videos work well, and I usually have a lot of questions about the production.

Another question that I hope is not disrespectful: does PCBWay and JLCPCB pay for brand placement during the video or was it just a tribute from your side?

by kh_hk

1/23/2026 at 6:27:46 PM

Man iphones have come a long way

by dangoodmanUT

1/23/2026 at 7:27:28 PM

My wife has worked in marketing for years and setting up photo shoots/video shoots has changed massively. A huge amount of the video and pictures that don't require a specialized lense are just done with feature phones these days.

by pixl97

1/23/2026 at 12:37:21 PM

Yo. You have to make videos. Then, seeing videos that you like, you secretly try to “steal” those ideas you articulated.

Just don’t tell anybody you’re a copy-cat.

by xtiansimon

1/23/2026 at 2:00:29 PM

"Good artists borrow. Great artists steal." -- me

by wpietri

1/23/2026 at 7:03:43 AM

FANTASTIC!!

I was just thinking about this the other day, and wondering about directionality...

For example, if you had a camera facing a space, and the receiving antenna was within that space... and you were able to (somehow?) from the antennas perspective, see the "direction" the frequency was coming from..

And then map the different specific frequencies within the desired bandwidth to colors... and of course intensity map like you have in the slit device..

And then "look through the camera"... you would see a live three dimensional overlay of all signals within range (colored!) "interacting" with the antenna... but kind of more the "looking through the camera" sort of view, like you could "see" how those waves were interacting..

And then wouldn't it be interesting to put a tin-foil hat to one side of the attennas.. and see how the waves change in real time... etc.!!!

(I guess it takes three antennas, to triangulate the field? Maybe all three can still be mounted on a single device in close proximity?)

by lucid-dev

1/23/2026 at 8:34:53 AM

> and you were able to (somehow?) from the antennas perspective, see the "direction" the frequency was coming from..

You can kind of do that quite easily at low frequencies, by measuring the phase of signals coming in from a pair of aerials. If you put two aerials a quarter of a wavelength apart and switch between them very quickly at audio rate, then you'll get a tone when there's a difference in phase. If there's no tone the two signals are exactly in phase - the two aerials are exactly the same distance from the transmitter.

If you look on some police cars you'll see a group of four aerials about 15cm apart stuck to the roof which used to be used for "Lojack" style trackers.

There are a whole bunch of circuit diagrams floating around for doing this kind of thing, with the simplest being Ye Olde 555 timer and a couple of PIN diodes!

by ErroneousBosh

1/23/2026 at 7:27:34 AM

Yes it has been done: https://youtu.be/sXwDrcd1t-E?si=V75bEPMT8qGbo1wG

by mzhaase

1/23/2026 at 9:47:57 AM

The title is: This ESP32 Antenna Array Can See WiFi

And every time I see something like this I like to remind to myself and imagine what spherical grid of Starlink satellites linked by laser is really capable of instead of mere internet as it is advertised.

by diimdeep

1/23/2026 at 3:48:25 PM

your link has the "si=" tracking parameter in it

by janez2

1/23/2026 at 7:49:17 AM

If you buy three (or more) Phillips Hue bulps you can have them respond to motion detected by things moving around and disturbing the radio waves they use to communicate. So they must have pretty much the kind of map you want, but I dont know how easy it is to export it.

by johanvts

1/23/2026 at 7:02:59 AM

It’s beautiful. I think I’ve seen something similar in a Ukraine war video where they use a device that lights up on specific frequencies that drones use.

by mrtksn

1/23/2026 at 7:10:26 AM

His other projects are so interesting. I love this one

https://rootkid.me/works/exhibit-a

by cush

1/23/2026 at 8:42:19 AM

Oh, that is fantastic.

What would really finish it for me, though, is if, when the button is released, the device shows a website, with URL visible, with a photo of the criminal, with added facial recognition and lookup of social media to find their identity.

What fun!

by CrzyLngPwd

1/23/2026 at 8:53:00 AM

The narration is very nice. Any idea of what the data could be? He mentions that it's legal for him to store but illegal to sell abroad and ranges from "bad to very bad".

by simgt

1/23/2026 at 10:23:24 AM

It's in teh description: "launching a fully functional darknet marketplace (http://spectretjag3wni6fzt445qwgokqlxnfz7fxkicj5efxjywlinibm...) that offers a trove of illegal data for sale across borders"

by abrookewood

1/23/2026 at 4:54:50 PM

> offers a trove of illegal data for sale

I'm precisely asking for speculation on what this data could be, which is the goal of the artist as stated in his video

by simgt

1/23/2026 at 7:30:36 PM

Stolen PII/identities/passwords are one of the most common you'll find.

by pixl97

1/24/2026 at 4:52:07 AM

Ah sorry, misunderstood. Probably credit cards etc

by abrookewood

1/23/2026 at 3:39:31 PM

I don't need that, I already have a Twitter account

by MPSimmons

1/23/2026 at 6:42:20 AM

Incredibly cool. I was really hoping to see the more ‘edge’ cases - take the light out to the middle of nowhere, walk towards it and away from it with just your phone or a Bluetooth speaker, see it react to your approach. The bit at the end about it shifting over the course of the day is cool, but I wish the effect was more visually apparent - it mostly just looked like random noise the whole time to me.

by mock-possum

1/23/2026 at 11:21:43 AM

I wanted to take it war driving around paris and the countryside, maybe i'll make a separate short video for that

by tzvc

1/23/2026 at 6:54:02 AM

This is fantastic. But the idea where you use a camera that can only see the wifi signals in the room like visible light is even more stunning. It would be even better if you could block out all light from the visible spectrum and only see the GHz band.

by dyauspitr

1/23/2026 at 11:30:09 AM

Sawing the first shot, I thought the LED candle on the coffee table was the device. That would have also been cool, having flickering affected not by wind, as with real candles, but by radio waves.

by asgerhb

1/23/2026 at 6:39:53 AM

Very cool, was there a conversion or look up table to convert db to gamma for more accurate human visualization?

by milleramp

1/23/2026 at 3:49:01 PM

I'm not sure what you mean

by tzvc

1/23/2026 at 6:35:55 PM

The db scale is logarithmic but doesn't match how our eyes sense light. So small changes in db may result in large visible light changes, or vise versa. Have you ever looked at a raw image, it doesn't look correct untill a gamma is applied, even though roughly the same information exists in both raw and gamma images. This is a similar concept. To do do this: db > linear > gamma This can be precomputed into a lookup table with the number of entries being the number of current steps, 8-bit 256 entries.

by milleramp

1/23/2026 at 7:38:33 PM

That's a great design and idea. Have you considered designing a light-based Morse code device? The light would be invisible to the naked eye, requiring special glasses/detector to translate either mechanically or digitally. The source light (e.g. neon, lamps, something new) would be encoded with encrypted messages, so it doesn’t look like obvious Morse code by using aspects of steganography where encrypted data would be hidden in pseudo-random light intensity/pulse patterns mimicking candle flicker, noise, etc.). It would require a custom protocol, error correction, obfuscation. All made on the cheap.

by SilentM68

1/23/2026 at 8:54:06 AM

A much simpler and less cool project would be to convert a slice of the RF spectrum into an RGB value with lowest frequencies mapped to red, highest to blue, and the resulting color being how we would perceive the mix.

by 01100011

1/23/2026 at 10:51:29 AM

That would still be cool - but what I really like about this is that it says something quite interesting about human existence, how we live, and in particular how we live in cities when we are in proximity to each other.

by saaaaaam

1/23/2026 at 9:01:13 AM

I once had a antenna with a lamp on it. It was used to detect best place for the radio. It just rectified the energy it received and used a very tiny light bulb

by Surac

1/23/2026 at 1:15:35 PM

Remember the days when you could just make art, without having to be a Content Creator?

Respect to the artist, I know I couldn’t do it.

by relaxing

1/23/2026 at 7:35:18 PM

You can still make art without being a content creator. I would assume with the accessibility to both knowledge and products more people than ever are.

With this said, if they are not content creators, you'll never know about them. That's not any different than the past were art was typically only known to those with in viewing range of said art.

by pixl97

1/23/2026 at 7:06:52 AM

I cannot find the YT video but an artist in residence did a short film with scratch-over of footage in an RF lab which tries to give a visual impression of the waves emitted by things present.

We're bathed in EMF. It's what light is, but aside from that we use electricity so much now, we're in a sea of radiation in other frequencies too.

by ggm

1/23/2026 at 10:11:00 AM

Very cool! I was having a conversation with my colleagues yesterday about building something to detect when you get scanned by a SAR (synthetic aperture radar) satellite (we're in earth observation), but you'd have to get a directional antenna to not be drowned out by terrestrial radio signals.

by fnands

1/23/2026 at 8:51:26 AM

All those inductors... Isn't there a cheaper way to drive those lights, e.g. using DC voltage+pwm?

by amelius

1/23/2026 at 9:54:30 AM

Those inductors are cheaper than what PCBWay charged for making that wooden box, I don't think their cost matters much here.

by seszett

1/23/2026 at 10:51:45 AM

Yes each LED channel has an inductor. I needed this because I wanted the LED to be constant current driven, to reduce flicker and improve their longevity

(and they cost like 5ct each)

by tzvc

1/23/2026 at 2:48:09 PM

What an excellent video.

Depsite visiting Hackernews multiple times a day, I am not a tech person. Seeing people creating such thing in a way I can undestand (which is maybe...10-15 % of the posts here ?) is so refreshing !

The editing is sharp, the setup looks so cool and the channel !

Thank you for making this !

by Mouvelie

1/27/2026 at 2:27:19 PM

Aaa, I misread the title and thought that it was powered by the radio waves, regardless still very cool!

by LoveMortuus

1/23/2026 at 11:01:10 AM

I just watched all the other videos of their pieces, and all of them are absolutely amazing conceptual explorations of our relationship with technology. Really amazing stuff

by sergioisidoro

1/23/2026 at 11:19:19 AM

The bit in the phone project where he cuts out the poem authors intro seems a bit scummy though, all that work he's making uncredited... then he finishes the video by showing him signing the piece.

I guess it's a good commentary on how tech people value other peoples work.

by SiempreViernes

1/23/2026 at 1:52:03 PM

I wasn't surprised by that, I studied in one of the best schools in France and that attitude was prevalent amongst students.

by curiousgal

1/23/2026 at 1:32:43 PM

Indeed, and the final result isn't particularly good as an art piece.

by fanatic2pope

1/23/2026 at 7:01:54 AM

This is such a neat project. The idea of translating invisible radio waves into visible light is mesmerizing — it feels like giving your surroundings a new sensory dimension.

by shawn10067

1/24/2026 at 1:48:57 PM

I often would love a camera similar to acoustic cameras / night vision cameras, but for RF. Like portable synthetic aperture radar.

by nerdsniper

1/23/2026 at 9:08:57 AM

Very appropriate soundtrack too:

https://youtu.be/B_gLxVZuk60

Uranium by Radioactiveman

by smellington

1/23/2026 at 10:52:16 AM

I had to dig deeep in my soundcloud to find it!

by tzvc

1/23/2026 at 4:28:41 PM

The lights sort of did this already on accident, but making a more robust audio-output version of this would be fascinating as well.

by pringularity

1/23/2026 at 10:42:36 AM

I'm glad we can all agree this is really cool

by alansaber

1/23/2026 at 5:29:55 PM

Yeah, same here. Also, I can't recall a time since back when I used to make music that I got actually jealous of someone else's abilities, but here I am. :)

by consumer451

1/23/2026 at 11:11:06 AM

you have everything right in front of your eyes, next if you add a transformer which convers these light signals into what they actually are then Voilà, you can see what's travelling in the air (Photos, conversations, music)

by sush1612

1/23/2026 at 11:12:32 AM

Except it’s encrypted with TLS

by levidos

1/23/2026 at 11:13:08 AM

not far away

by sush1612

1/23/2026 at 7:08:00 AM

The sounds were so cool -straight out of sci-fi movie.

by cush

1/23/2026 at 10:51:45 AM

Traditional fix for coil hum is a blob of glue from a hot glue gun.

It is fun making it part of the show though.

by nickcw

1/23/2026 at 6:43:09 PM

would look good if he put a heavily frosted material infront. Right now is gonna cause more headaches than a 5g transmitter in your room

by m3kw9

1/23/2026 at 2:52:12 PM

Looks like Circuit Python is used?

by halfmatthalfcat

1/23/2026 at 6:36:29 AM

I love your poetry on a phone project so muchhhh

by segalord

1/23/2026 at 7:04:46 AM

Someone makes a kickstarter out of it please

by mw67

1/23/2026 at 6:36:09 AM

Very cool!

by ebhn

1/23/2026 at 4:15:46 PM

very very impressive.

by dwa3592

1/23/2026 at 10:54:10 AM

very very cool !

by steeve

1/23/2026 at 10:42:40 AM

Why do you need another source of irritation in your room?

by pKropotkin

1/23/2026 at 10:50:23 AM

I don't think anyone is arguing that you NEED this. But it's the intersection of technology and art, and says something about the way we live. You can view it as nothing more than an irritation, but I think that's a shame.

by saaaaaam

1/23/2026 at 8:31:56 PM

Are you asking why he needs another light? His project doesn’t make radio waves.

by bethekidyouwant