Fluidic Logic Systems Offer Silicon-Free Computing
While silicon dominates modern processing, fluidic logic systems that compute using air and water offer a highly durable alternative for robotics and extreme environments.
Fluidic logic bypasses traditional silicon by using gases or liquids to perform binary calculations. Historical milestones prove the viability of this approach, such as Univac building the Fluid Operated Digital Automatic Computer (FLODAC) in the 1960s with 250 fluidic NOR gates. Decades earlier, Phillips constructed a dozen analogue fluidic computers in the late 1940s to model macroeconomic flows. More recently, Harvard University's Wyss Institute developed the Octobot, a soft robot that operated for eight minutes using a hydrogen peroxide reservoir and a platinum catalyst. Even commercial aviation has utilized the technology, with the 1970s-era DC-10 airliner employing a bistable Coanda effect amplifier to manage its thrust reversers.
Today, researchers are scaling down these systems. The University of Michigan has designed a miniature 8-bit fluidic microprocessor, while commercial enterprises like Cepheid utilize microfluidic principles in its GeneXpert system for automated gene sequencing. NASA has even proposed the Automaton Robot for Extreme Environments, a wind-turbine-powered Venus rover that would rely on fluid and mechanical control logic to survive conditions that would destroy standard electronics.
For hardware practitioners, fluidic computing presents stark trade-offs in speed and scale. The fastest microfluidic actuators switch in about one millisecond, whereas electronic transistors operate in the picosecond to nanosecond range. This makes fluidic logic elements 1,000 to 100,000 times slower than micro-electronics, and they are at least 1,000 times larger. Additionally, because fluidic signals travel at the speed of sound rather than the speed of light, they are inherently a million times slower. Replicating a classic Commodore 64 CPU, which has 3,500 transistors and 64 kilobytes of RAM, would require fluidic transistors measuring 100 to 200 micrometres per side, resulting in a system that is thousands of times slower and prone to pressure leaks.
Despite these limitations, fluidic logic excels where electronics fail. It eliminates spark risks in hazardous industrial environments and withstands harsh wash-down cycles. For soft robotics and prosthetics, fluidic logic allows the control system to be integrated directly into the physical actuators. This creates a self-regulating, distributed system where the logic acts like a physical reflex, responding directly to pressure changes without requiring complex electronic sensors or external motors.
This is our own summary of reporting by The Chip Letter
