The Light Bulb Becomes a Digital Library of Banned Books: The Absurd Project
A high-profile project has demonstrated how technology can be bent to unexpected purposes, transforming a Wi-Fi smart light bulb into a true "digital repository" of banned books. The initiative, dubbed the Banned Book Library, has seen a developer reprogram the firmware of a common light bulb to host a local web server, making otherwise prohibited works accessible via a Wi-Fi hotspot.
Inspired by literary works like Library by Ben Brown and Unauthorized Bread by Cory Doctorow, the idea aims to create a discreet and affordable dissemination system. By installing these light bulbs in public places, anyone nearby with a Wi-Fi-enabled device can connect and access content, turning a mundane object into a barely detectable knowledge access point at low cost.
The starting point was a smart bulb with a 4 MB ESP32C3 chip, preloaded with the open-source Tasmota firmware. Initially, the developer considered directly modifying Tasmota, but its complexity and many unnecessary features for the project pushed towards a leaner solution. Moreover, the idea of expanding storage with a microSD card was quickly abandoned: physical integration would have required complex soldering and dismantling of the bulb, compromising the integrity and safety of the device as a clandestine "dead drop."
How Rick Osgood's "Library Bulb" Works
The real technological challenge shifted to managing the 4 MB internal memory. To overcome the limitation of only 320 KB initially available for data, the developer adopted the official ESP-IDF development environment, abandoning the Arduino IDE for more granular control. This allowed access to modify the partition table, a risky but necessary procedure. The operation involved reducing the main firmware partition (from 2880 KB to 1152 KB) and expanding the data partition (spiffs) from 320 KB to a whopping 2 MB, a substantial increase to host more e-books.
The custom firmware integrates a web server and a captive portal. The latter is a key feature for detectability: when a user connects to the light bulb's Wi-Fi hotspot, they are automatically redirected to the library webpage, regardless of the URL typed. This was achieved through a DNS server configured to respond with the device's IP to any requests and intercepting the "ping" calls from operating systems (Windows, Android, iOS) for the presence of an authentication portal.
Another significant aspect concerned operational security (OPSEC). The original Tasmota firmware stored Wi-Fi credentials in plain text in the NVS (Non-Volatile Storage) partition. To prevent a "lost" bulb from revealing its creator's home network, the developer implemented their own minimalist "safeboot" firmware. This firmware, after erasing the NVS partition, allows for more secure and discreet Over-The-Air (OTA) updates.
The web interface of the Banned Book Library is intentionally simple, featuring graphics inspired by the cyberpunk imaginary and a clear list of books, including title, author, and reason for censorship. The password-protected admin panel offers a stealth functionality: it allows users to adjust the color temperature of the LED to ensure the bulb blends perfectly with the existing lighting in an environment, reducing the chances of being noticed. The color configuration is saved in NVS memory, ensuring that the bulb retains the setting even after a reboot.
Despite the limited storage capacity to a few e-books (about 350 KB each), the developer embraced this restriction. This means that every "dead drop" will become a curated personal selection of texts, reflecting the individual choices of its creator. This limitation encourages greater reflection on content selection and promises a unique discovery experience for users, who may find different installations in every corner of the city.
Among future ideas, there is talk of more granular RGB color control via sliders and, above all, the possibility of creating a mesh network between multiple light bulbs. This would allow devices to share content, forming a distributed library accessible from anywhere on the network. The technological concreteness of the economical ESP32 chips continues to open new pathways in the field for high-profile projects. The complete article on the project is available on this page.