Clever hacker fits 537,000 domains in a tiny $5 ESP32 ad-blocking dongle — firmware uses only around 50KB of RAM and can answer blocked lookups in 10 milliseconds
Summary
Tom's Hardware covers a DIY ESP32-based ad-blocking dongle that can block about 537,000 domains using a 40-bit hash scheme. The firmware stores a hashed domain database in around 50 KB of RAM and answers blocked lookups in roughly 10 milliseconds, with the device leveraging the ESP32-C3’s limited RAM and flash. The article highlights the hardware details, trade-offs (e.g., OTA partitions affecting capacity), and positions the project as a tiny, network-wide backup DNS option rather than a full replacement for Pi-hole or AdGuard Home.