A builder called soiboi soft has made a vacuum-driven dot matrix display that runs Snake and Pong using no electronics at the pixel level. Each pixel is a cavity behind a flexible silicone sheet. A pneumatic transistor, an air channel gated by a vacuum control line, pulls the sheet inward to create a visible shadow. The entire display logic is microfluidic.
The 16-pixel prototype uses 8 control channels, 4 rows and 4 columns, multiplexed to address each pixel individually. The transistors act as one-way valves, meaning pixels hold state even under manual pressure. That passive memory behavior is the detail worth pausing on: add a state-sensing circuit and this becomes a functional touchscreen with no electronic components in the display layer. Scaling to 64 pixels introduced a warping problem in the 3D-printed parts that broke pixel seals. The fix was vacuum-bag annealing against a flat glass plate at 60 degrees Celsius for several hours, combined with raised sealing rings in the print geometry.
The full 64-pixel display can render letters, numerals, animations, and playable games. Refresh rate is slow but usable. The original article is worth reading for the specifics of the pneumatic multiplexing scheme and the solenoid valve mounting solution using Luer lock adapters, both of which point toward where this hardware is headed as a platform.
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