Developer builds $2 ESP32-C3 DNS ad-blocker blocking 537k domains using 40-bit hash storage in flash memory, no PSRAM needed—beats Pi-hole hardware costs by storing hashes instead of strings.

GitHub - M-Abozaid/esp32-c3-adblock: Pi-hole-class DNS ad-blocker on a $2 ESP32-C3 (no PSRAM): 537k domains as 40-bit FNV-1a hashes in flash, binary-searched. UDP DNS sinkhole + web dashboard. https://youtube.com/shorts/RaxszOUMi8E?feature=share

日本語 README A Pi-hole-style DNS ad-blocker that runs on a $2 ESP32-C3 — no PSRAM required. 📰 Featured on Tom's Hardware, XDA Developers, and Korben. The trick everyone misses: you don't need to keep the blocklist in RAM. Store the domains as sorted 40-bit hashes in flash and binary-search them. 140,000+ domains fit in ~0.7 MB of flash and are matched in ~10 ms, using ~50 KB of RAM. query in ──▶ extract domain ──▶ FNV-1a hash (+ parent suffixes) ──▶ binary-search the flash hash table ├─ hit ──▶ ...