frontpage.
newsnewestaskshowjobs

Made with ♥ by @iamnishanth

Open Source @Github

fp.

Open in hackernews

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

https://www.youtube.com/watch?v=moBCOEiqiPs
160•codetheweb•4h ago
https://rootkid.me/works/spectrum-slit

Comments

ebhn•3h ago
Very cool!
segalord•3h ago
I love your poetry on a phone project so muchhhh
milleramp•3h ago
Very cool, was there a conversion or look up table to convert db to gamma for more accurate human visualization?
mock-possum•3h ago
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.
dyauspitr•3h ago
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.
shawn10067•3h ago
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.
mrtksn•3h ago
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.
lucid-dev•3h ago
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?)

mzhaase•3h ago
Yes it has been done: https://youtu.be/sXwDrcd1t-E?si=V75bEPMT8qGbo1wG
diimdeep•42m ago
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.

phrotoma•13m ago
See also: https://youtu.be/o6WHhqDHSQ4
johanvts•2h ago
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.
ErroneousBosh•1h ago
> 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!

amelius•1h ago
This is sort of that idea with sound:

https://www.youtube.com/watch?v=jL2JK0uJEbM

mw67•3h ago
Someone makes a kickstarter out of it please
ggm•3h ago
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.

cush•3h ago
The sounds were so cool -straight out of sci-fi movie.
cush•3h ago
His other projects are so interesting. I love this one

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

CrzyLngPwd•1h ago
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!

simgt•1h ago
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".
abrookewood•7m ago
It's in teh description: "launching a fully functional darknet marketplace (http://spectretjag3wni6fzt445qwgokqlxnfz7fxkicj5efxjywlinibm...) that offers a trove of illegal data for sale across borders"
louwrentius•2h ago
Let's call this what it really is: it's an art project. It's not 'just' a cool technical work.

[0]: https://news.ycombinator.com/item?id=46729428

amelius•1h ago
All those inductors... Isn't there a cheaper way to drive those lights, e.g. using DC voltage+pwm?
seszett•36m ago
Those inductors are cheaper than what PCBWay charged for making that wooden box, I don't think their cost matters much here.
01100011•1h ago
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.
Surac•1h ago
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
smellington•1h ago
Very appropriate soundtrack too:

https://youtu.be/B_gLxVZuk60

Uranium by Radioactiveman

TrackerFF•40m ago
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.

fnands•19m ago
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.

Google is ending full-web search for niche search engines

https://programmablesearchengine.googleblog.com/
69•01jonny01•52m ago•36 comments

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

https://www.youtube.com/watch?v=moBCOEiqiPs
161•codetheweb•4h ago•29 comments

Replacing Protobuf with Rust to go 5 times faster

https://pgdog.dev/blog/replace-protobuf-with-rust
20•whiteros_e•1h ago•9 comments

Proton Spam and the AI Consent Problem

https://dbushell.com/2026/01/22/proton-spam/
191•dbushell•3h ago•98 comments

Show HN: isometric.nyc – giant isometric pixel art map of NYC

https://cannoneyed.com/isometric-nyc/
935•cannoneyed•17h ago•185 comments

GPTZero finds 100 new hallucinations in NeurIPS 2025 accepted papers

https://gptzero.me/news/neurips/
840•segmenta•19h ago•442 comments

Capital One to acquire Brex for $5.15B

https://www.reuters.com/legal/transactional/capital-one-buy-fintech-firm-brex-515-billion-deal-20...
302•personjerry•13h ago•230 comments

AI Is a Horse (2024)

https://kconner.com/2024/08/02/ai-is-a-horse.html
19•zdw•3d ago•3 comments

Why does SSH send 100 packets per keystroke?

https://eieio.games/blog/ssh-sends-100-packets-per-keystroke/
478•eieio•15h ago•264 comments

Ghostty's AI Policy

https://github.com/ghostty-org/ghostty/blob/main/AI_POLICY.md
5•mefengl•40m ago•1 comments

I was banned from Claude for scaffolding a Claude.md file?

https://hugodaniel.com/posts/claude-code-banned-me/
545•hugodan•15h ago•462 comments

TI-99/4A: Leaning More on the Firmware

https://bumbershootsoft.wordpress.com/2026/01/17/ti-99-4a-leaning-more-heavily-on-the-firmware/
33•ibobev•4d ago•16 comments

Qwen3-TTS family is now open sourced: Voice design, clone, and generation

https://qwen.ai/blog?id=qwen3tts-0115
600•Palmik•20h ago•187 comments

Scaling PostgreSQL to power 800M ChatGPT users

https://openai.com/index/scaling-postgresql/
190•mustaphah•13h ago•83 comments

Douglas Adams on the English–American cultural divide over "heroes"

https://shreevatsa.net/post/douglas-adams-cultural-divide/
449•speckx•20h ago•439 comments

A gaming success story: how Warhammer became one of Britain's biggest companies

https://www.theguardian.com/lifeandstyle/2026/jan/18/a-gaming-success-story-how-warhammer-became-...
34•GeoAtreides•4d ago•35 comments

Bugs Apple Loves

https://www.bugsappleloves.com
642•nhod•8h ago•279 comments

Your app subscription is now my weekend project

https://rselbach.com/your-sub-is-now-my-weekend-project
357•robteix•4d ago•263 comments

Improving the usability of C libraries in Swift

https://www.swift.org/blog/improving-usability-of-c-libraries-in-swift/
116•timsneath•10h ago•10 comments

Project Mercury and the Sofar Bomb

https://www.thequantumcat.space/p/project-mercury-and-the-sofar-bomb
9•verzali•4d ago•0 comments

Why medieval city-builder video games are historically inaccurate (2020)

https://www.leidenmedievalistsblog.nl/articles/why-medieval-city-builder-video-games-are-historic...
142•benbreen•10h ago•88 comments

Writing First, Tooling Second

https://susam.net/writing-first-tooling-second.html
33•blenderob•4d ago•4 comments

Show HN: Txt2plotter – True centerline vectors from Flux.2 for pen plotters

https://github.com/malvarezcastillo/txt2plotter
19•tsanummy•3d ago•5 comments

Turso is an in-process SQL database, compatible with SQLite

https://github.com/tursodatabase/turso
118•marklit•3d ago•72 comments

Stunnel

https://www.stunnel.org/
76•firesteelrain•10h ago•27 comments

'Askers' vs. 'Guessers' (2010)

https://www.theatlantic.com/national/2010/05/askers-vs-guessers/340891/
149•BoorishBears•22h ago•97 comments

Why are there so many CPU bugs nowadays

https://mas.to/@gabrielesvelto/115939583202357863
16•riffraff•1h ago•4 comments

CSS Optical Illusions

https://alvaromontoro.com/blog/68091/css-optical-illusions
185•ulrischa•16h ago•15 comments

Launch HN: Constellation Space (YC W26) – AI for satellite mission assurance

40•kmajid•17h ago•15 comments

Show HN: Text-to-video model from scratch (2 brothers, 2 years, 2B params)

https://huggingface.co/collections/Linum-AI/linum-v2-2b-text-to-video
83•schopra909•17h ago•15 comments