[HN Gopher] Espargos: ESP32-based WiFi sensing array
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       Espargos: ESP32-based WiFi sensing array
        
       Author : leoedin
       Score  : 119 points
       Date   : 2025-02-17 13:54 UTC (9 hours ago)
        
 (HTM) web link (espargos.net)
 (TXT) w3m dump (espargos.net)
        
       | leoedin wrote:
       | This project uses an array of ESP32s and some clever calibration
       | techniques to do pretty accurate localisation of WiFi signals.
       | 
       | There's an excellent companion video here:
       | https://www.youtube.com/watch?v=sXwDrcd1t-E
        
       | Ecco wrote:
       | Very cool! Website bug report (hoping somebody sees that): on my
       | phone (iPhone latest iOS) the videos would automatically play in
       | full screen when scrolling the page. Really annoying :)
        
         | saaaaaam wrote:
         | Same for me. Though I just assumed it was some sort of annoying
         | "feature".
        
         | Jeija wrote:
         | Oops, never tested the website on Safari / iOS. I will look
         | into this at some point, opened a GitHub issue for myself so
         | that I will remember:
         | https://github.com/ESPARGOS/espargos.github.io/issues/1
        
       | tonetegeatinst wrote:
       | Is this locked to WiFi spectrum, or could the antennas be swappen
       | for whatever frequency band you want to target?
       | 
       | Say starlink frequency for tracking or The NOAA satellites?
        
         | gfkclzhzo wrote:
         | ESP32 will be just 2.4ghz, and the bandwidth of the antennas
         | will also limit.
         | 
         | Totally doable to make a wideband version with different
         | hardware. This is called a phased array, which is common in
         | radar applications (e.g. Aegis cruisers).
        
           | leptons wrote:
           | Espressif has a new dual-band chip that does 2.4ghz and 5ghz
           | wifi. That isn't the subject of this article, but ESP32 is
           | gaining some new wifi capabilities.
        
             | Jeija wrote:
             | I'm currently experimenting with ESP32-C5 engineering
             | samples provided by Espressif, so hopefully some future
             | ESPARGOS revision will be 5GHz-capable :)
             | 
             | But yeah, as far as I can tell, the chip can only extract
             | CSI from WiFi (unless there is some hidden raw I/Q sample
             | debug mode or something).
        
               | ipdashc wrote:
               | This project is amazing! I know there's some prior art,
               | but I feel like I've never seen anything wifi-related
               | moving so... smoothly? (With that high of an
               | update/sample rate, I guess?) as your visualizations do.
               | 
               | I do have one question that wasn't quite clear to me, in
               | case you happen to see this. There's a bunch of mentions
               | of Channel State Information, but Google doesn't give a
               | ton of info on it. So I'm just wondering, is CSI a
               | "client-side" thing provided by the ESP32 for any Wi-Fi
               | connection, or is it some special protocol feature that
               | the AP or client have to enable?
        
       | SEJeff wrote:
       | I'd note that Xandem while a total flop commercially, does own
       | patents on tomographic motion detection.
       | 
       | It's a shame honestly, it was a really cool product.
        
       | ChrisArchitect wrote:
       | Earlier video: https://www.youtube.com/watch?v=sXwDrcd1t-E
       | 
       | (https://news.ycombinator.com/item?id=43062982)
        
       | slicktux wrote:
       | Hmm, seems like I'll be able to replace my cantenna with this to
       | find malicious IoT devices spamming the airwaves with DeAuth
       | attacks...! Imagine being able to catch crooks using Flipper
       | Zeros to defeat wireless cameras...can track them in real time ;)
        
         | MisterTea wrote:
         | > Imagine being able to catch crooks using Flipper Zeros to
         | defeat wireless cameras...can track them in real time ;)
         | 
         | One of the reasons I run Ethernet to everything.
         | 
         | Also, I assume you work in security if you deal deal with
         | malicious WiFi devices and sophisticated crooks?
        
         | adfm wrote:
         | +1 for cantenna reference.
        
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