Screen Savers

The fact that a lot of computing hardware has become inexpensive enough to be disposable after a couple years is a very good thing. The fact that much of this hardware actually is disposed of is not so good at all. The batteries, chips, and other components powering this hardware contain toxic chemicals, so dumping them in landfills by the truckload is a terrible idea. Not to mention that the hardware is still quite useful, even if it is a little dated. I mean, if a Commodore 64 can run TensorFlow, then surely a laptop from three years ago still has value.

One of the worst offenders is the Chromebook. These inexpensive laptops have planned obsolescence built into them in a way that would make even Apple blush. Once they stop receiving software updates, they quickly become useless for their intended purpose. There are tons of them out there too, as schools love to buy them in bulk for use by students and staff. And these schools also like to set up janky authentication systems that go offline over time, without which the Chromebooks cannot be used.

Of course these laptops do contain some decent computing power inside of them, if only it could be freed from its artificial bonds. When Varun Biniwale and Aksel Salmi found out that their school was about to trash a large number of old Chromebooks, they decided to repurpose them rather than let all of those beautiful displays and processors go to waste. The plan they came up with involved turning ten of these aging machines into a video wall.

Since the devices were tied to an enterprise enrollment system, they could not be used without logging into the school’s Google account — an impossible task for decommissioned laptops. To get around this issue, the team had to remove ChromeOS entirely and replace it with a lightweight Linux distribution.

As a first step in this process, a ChromeOS firmware recovery script was used to gain access to the motherboards’ more advanced settings. However, some laptops still refused to enter developer mode (which is necessary to install a new OS) due to enterprise restrictions. To bypass this, they removed the write protection screw from each motherboard and flashed the firmware with coreboot, an open-source BIOS replacement. This step finally freed the laptops from their restrictions.

With usable hardware, attention could be shifted to the software component of the video wall. Each Chromebook needed to play its own portion of a wide-format video while staying in sync with the others. Tests showed that standard streaming methods, like VLC’s network streaming, did not offer the precise synchronization required. So instead Biniwale leveraged his prior experience with Socket.io, a WebSocket-based library, to develop a custom system called c-sync. This system allowed all laptops to communicate in real time, ensuring that each screen displayed the correct portion of the video at the right moment.

However, even with c-sync, discrepancies in network latency and device performance caused slight desynchronization. The solution turned out to be quite simple — modifying the video player to trigger a start event only when the slowest laptop had finished loading. This approach kept all screens synchronized despite their individual hardware differences.

As a finishing touch, laser-cut acrylic backplates were created to secure the laptop motherboards and displays to the wall. Power cables were spliced together to reduce clutter, and each power supply ran two devices.

The final result is not quite perfect — differences in panel quality and viewing angles make the video wall somewhat inconsistent. But the project is still a powerful example of how old hardware can be given new life rather than being discarded.