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Abstract Mobile microrobots, which can navigate, sense, and interact with their environment, could potentially revolutionize biomedicine and environmental remediation. Many self-organizing microrobotic collectives have been developed to overcome inherent limits in actuation, sensing, and manipulation of individual microrobots; however, reconfigurable collectives with robust transitions between behaviors are rare. Such systems that perform multiple functions are advantageous to operate in complex environments. Here, we present a versatile microrobotic collective system capable of on-demand reconfiguration to adapt to and utilize their environments to perform various functions at the air–water interface. Our system exhibits diverse modes ranging from isotropic to anisotrpic behaviors and transitions between a globally driven and a novel self-propelling behavior. We show the transition between different modes in experiments and simulations, and demonstrate various functions, using the reconfigurability of our system to navigate, explore, and interact with the environment. Such versatile microrobot collectives with globally driven and self-propelled behaviors have great potential in future medical and environmental applications.Free, publicly-accessible full text available December 1, 2023
null (Ed.)The recycling of used integrated circuits (ICs) has raised serious problems in ensuring the integrity of today's globalized semiconductor supply chain. This poses a serious threat to critical infrastructure due to potentially shorter lifetime, lower reliability, and poorer performance from these counterfeit new chips. Recently, we have proposed a highly effective approach for detecting such chips by exploiting the power-up state of on-chip SRAMs. Due to the symmetry of the memory array layout, an equal number of cells power-up to the 0 and 1 logic states in a new unused SRAM; this ratio gets skewed in time due to uneven NBTI aging from normal usage in the field. Although this solution is very effective in detecting recycled ICs, its applicability is somewhat limited as a large number older designs do not have large on-chip memories. In this paper, we propose an alternate approach based on the initial power-up state of scan flip-flops, which are present in virtually every digital circuit. Since the flip-flops, unlike SRAM cells, are generally not perfectly symmetrical in layout, an equal number of scan cells will not power-up to 0 or 1 logic states in most designs. Consequently, a stable time zero reference of 50% logicmore »