Soft Non-Volatile Memory for Non-Electronic Information Storage in Soft Robots

Pneumatically operated soft robots require complex infrastructure for their operation: microcontrollers must control hard pneumatic valves via power electronics. Although soft digital logic gates based on soft valves have been demonstrated as a replacement for electronic control, the development of memory from logic gates is cumbersome (three logic gates with mono-stable membranes for the development of a single S-R latch), and such memory is only capable of holding, but not storing, information; after a power reset, the membranes relax to their idle states, and the information is lost. In this work, we introduce a soft memory device with a bistable membrane that allows the permanent storage of binary information in soft materials, and we demonstrate its writing and erasing operations. We also introduce a new type of pneumatically-driven soft display, the soft bubble display. We connect the display to our soft memory device to visualize the information that is held in the memory. Our work highlights the importance of material-based memory and its future use for programming soft robots.