On May 14, Polish engineer Maurycy published a live website hosted on an 8-bit AVR64DD32 microcontroller costing $1. The chip, running at 24 MHz with 8 kB RAM and 64 kB flash, serves a single-page site over a serial SLIP connection instead of Ethernet, avoiding the need for external networking hardware.
The AVR64DD32 microcontroller, similar to the Arduino's Atmega328, features an 8-bit AVR core clocked at 24 MHz, 8 kB static RAM, 64 kB flash memory, and 256 bytes of EEPROM. It operates on 1.8–5.5 volts and is priced at $1. Maurycy chose it for its low cost and single programming pin, which simplified the build compared to older Atmega models.
Ethernet was ruled out due to speed constraints. The slowest Ethernet standard, 10BASE-T, transmits at 10 megabits per second, but Manchester encoding doubles the wire rate to 20 megabits. The AVR's peripherals and I/O pins max out at 12 MHz, making real-time Ethernet packet generation impossible without external hardware, which Maurycy avoided to complete the project quickly.
Instead of Ethernet, Maurycy used Serial Line Internet Protocol (SLIP), an old standard defined in RFC 1055. SLIP wraps packets in 0xC0 bytes and escapes 0xC0 and 0xDB bytes to avoid ambiguity. The protocol was widely used in dial-up modems, which created serial links over phone lines, and remains supported in modern Linux via commands like `slattach`.
The hardware setup is minimal: the microcontroller connects directly to a USB-serial adapter, drawing power from its 5-volt rail. Maurycy added LEDs and a diode for visual feedback and reverse-polarity protection. The entire system consumes only a few milliwatts, making it feasible to run off a single USB cable without additional power sources.
To route packets across networks, the microcontroller implements a stripped-down IP stack. Modern operating systems disable IP fragmentation, and IPv6 removed it entirely, simplifying the implementation. The server swaps source and destination addresses in received packets to generate response headers, resetting the TTL counter to ensure delivery.
TCP proved more challenging. Maurycy spent several days writing a custom implementation to track connection states, retransmit lost packets, and handle edge cases. The result is functional but buggy, with lingering issues in packet handling. HTTP was not implemented; the server sends a hardcoded response for a single URL, limiting the site to one page.
A demo video shows the website loading in a browser, confirming the setup works. However, sharing the site publicly requires a routable IPv4 address, which Maurycy notes is both expensive and impractical for this project. The server remains accessible only to devices on the same local network or via direct serial connection.
Maurycy published the project's source code (`www.c`) and a prebuilt binary (`www.elf`) on his blog. The hardware schematic is also available, showing the microcontroller's direct connection to the serial adapter. The project demonstrates how legacy protocols like SLIP can enable internet connectivity on ultra-low-power devices without modern networking hardware.