Now that's one way to block annoying online ads developer uses a $5 dongle to squeeze in 537,000 domains into just 4MB of flash memory

Date:
Wed, 22 Jul 2026 23:20:00 +0000

Description:
Egyptian developer ZedAxis has demonstrated his $5 ad-blocking dongle in a YouTube video, with the device said to be capable of blocking over 500,000 domains

FULL STORY ======================================================================Copy link Facebook X Whatsapp Reddit Pinterest Flipboard Threads Email Share this article 0 Join the conversation Follow us Add us as a preferred source on Google Newsletter Subscribe to our newsletter Egyptian developer demonstrates how to block ads with an ESP32-C3 "SuperMini" board ESP32 ad-blocking dongle costs just $5 to build 537,000 blacklisted domains are stored in the devices 4MB of flash memory When online ads become a problem, ad-blocking software is a good idea, used in conjunction with dedicated hardware like a Raspberry Pi running Pi-Hole. But what if the device is rebooting or otherwise out of action? Egyptian developer ZedAxis claims to have developed a solution that might inspire a rethink on how online whitelisting and blacklisting is processed.

Relying on a sub-$5 ESP32-based mini board, the device somehow squeezes over 500,000 domains into paltry 4MB of onboard flash storage. The build has been demonstrated on YouTube , with the video of the DNS sinkhole apparently providing how simple it is to set up. All the hard work has been done by ZedAxis, with the code available via GitHub. Latest Videos From Watch full video here: What is an ESP32-C3? ZedAxis has built the compact Pi-Hole substitute from a $5 ESP32-C3 SuperMini board, easily available from online stores (currently 3.50 on the UK Amazon ). These devices feature USB-C for power, Bluetooth 5.0, and crucially for a project like this, Wi-Fi.

The board has been paired with a USB adapter and a 3D-printed case to enable it to be plugged into a power source in this case, the back of a router, but it could be a TV, console, or any other always-on device with an unused USB port. Direct access to the device is available through a web dashboard, it supports mDNS for easy discovery, and can download over-the-air (OTA)
updates. You may like Hundreds of thousands at risk as NordVPN uncovers sophisticated adware campaign hidden in 50,000 pirate sites This pocket-sized dongle enables cross-platform remote control with hardware security This DIY retro-style mini-TV plays classic NES games and movies

Code for the project is available on the developers GitHub , where the
unusual compression that shrinks over 500,000 domains into 4MB of flash storage is explained. Isnt that a lot of domains for 4MB? I built a $2 ad-blocker for my whole network - YouTube Watch On Strictly speaking, 4MB should not be able to hold 500,000 domains. As described on the projects GitHub, the actual figure is around half that (141,000 taking up ~2.5 MB of RAM). So how are the 537,000 domains squeezed into 4MB of RAM? Are you a pro? Subscribe to our newsletter Sign up to the TechRadar Pro newsletter to get
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The board chosen is specifically free of PSRAM (so it just has the flash) and rather than 32-bit or 64-bit, hashes the domains into 40-bit FNV-1a, an algorithm designed for speed and low-collision rates. So, 141,000 domains can be squeezed into 0.7MB of flash, with under 50 KB of RAM apportioned for matching the blacklisted ad domains.

In most cases, the blacklist is limited to around 250,000 domains as OTA firmware updates need around 1.3MB of the flash. But this can be determined when the device is set up and the first blacklist pull is made. Other
features are set to be added to this project, including set up as a DHCP server.

The big question is, could this be adopted by, say, small businesses looking for a reduction in broadband bandwidth being eaten by ad networks? Follow TechRadar on Google News and add us as a preferred source to get our expert news, reviews, and opinion in your feeds.



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Link to news story: https://www.techradar.com/pro/now-thats-one-way-to-block-annoying-online-ads-d eveloper-uses-a-usd5-dongle-to-squeeze-in-537-000-domains-into-just-4mb-of-fla sh-memory


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