Playing Snake with a Pneumatic Display

[soiboi soft]’s vacuum-driven dot matrix display is part suction gripper, part touchscreen, and altogether impressive. Its display capabilities are entirely shadow-based, with each pixel being made of a cavity behind …. Playing Snake with a Pneumatic Display.

Its display capabilities are entirely shadow-based, with each pixel being made of a cavity behind a flexible silicone sheet; when the display’s microfluidic logic circuitry activates a pixel, a vacuum pump pulls the sheet inwards, creating a visible hollow. As in previous iterations, the display’s control circuitry is built around a pneumatic “transistor”, which allows an air channel to be opened or closed by applying vacuum to a control channel. As a first test, [soiboi soft] built a 16-pixel dot matrix display.

Eight control channels – four row and four column channels – are multiplexed to individually control each pixel. The transistors act like one-way valves, so the pixels hold their state, even when pressed in by hand; simply add some circuitry to read a pixel’s state, and it would be a fully-functioning touchscreen. The supporting pneumatics also got an upgrade; the solenoid valves now cleanly mount to the back of the board, and the vacuum pump connects via a Luer lock adapter.

The 3D printing used to make certain parts and silicone molds caused issues when scaling up to a 64-pixel display, however.