ESP32-C3 Based Ad Blocker for Router

Developer ZedAxis has created an open-source ad blocker that can be installed directly into a router. The device is built on the microscopic ESP32-C3 board, which costs about two dollars.

The device is powered by the router's USB port and connects to the network via Wi-Fi. After flashing and configuration, the device is set as the DNS server, after which it automatically begins blocking requests to advertising domains.

The device's internal memory is limited: only 400 KB of RAM and 4 MB of flash memory are available. To save space, the author uses short digital fingerprints for addresses, allowing a list of 140,000 domains to fit in just 0.7 MB.

The full source code of the project, detailed installation instructions, and a 3D model of the case are available for free download on GitHub.