  The control of pneumatically driven soft robots typically requires
electronics. Microcontrollers are connected to power electronics that switch
valves and pumps on and off. As a recent alternative, fluidic control methods
have been introduced, in which soft digital logic gates permit multiple
actuation states to be achieved in soft systems. Such systems have demonstrated
autonomous behaviors without the use of electronics. However, fluidic
controllers have required complex fabrication processes. To democratize the
exploration of fluidic controllers, we developed tube-balloon logic circuitry,
which consists of logic gates made from straws and balloons. Each tube-balloon
logic device takes a novice five minutes to fabricate and costs $0.45.
Tube-balloon logic devices can also operate at pressures of up to 200 kPa and
oscillate at frequencies of up to 15 Hz. We configure the tube-balloon logic
device as NOT-, NAND-, and NOR-gates and assemble them into a three-ring
oscillator to demonstrate a vibrating sieve that separates sugar from rice.
Because tube-balloon logic devices are low-cost, easy to fabricate, and their
operating principle is simple, they are well suited for exploring fundamental
concepts of fluidic control schemes while encouraging design inquiry for
pneumatically driven soft robots
