Liquid Marble Interaction Gate for Collision-Based Computing

Abstract

Liquid marbles are microlitre droplets of liquid, encapsulated by self-organised hydrophobic particles at the liquid/air interface. They offer an efficient approach for manipulating liquid droplets and compartmentalising reactions in droplets. Digital fluidic devices employing liquid marbles might benefit from having embedded computing circuits without electronics and moving mechanical parts (apart from the marbles). We present an experimental implementation of a collision gate with liquid marbles. Mechanics of the gate follows principles of Margolus' soft-sphere collision gate. Boolean values of the inputs are given by the absence (False) or presence (True) of a liquid marble. There are three outputs: two outputs are trajectories of undisturbed marbles (they only report True when just one marble is present at one of the inputs), one output is represented by trajectories of colliding marbles (when two marbles collide they lose their horizontal momentum and fall), this output reports True only when two marbles are present at inputs. Thus the gate implements AND and AND-NOT logical functions. We speculate that by merging trajectories representing AND-NOT output into a single channel one can produce a one-bit half-adder. Potential design of a one-bit full-adder is discussed, and the synthesis of both a pure nickel metal and hybrid nickel/polymer liquid marble is reported.

Evaporation, Lifetime, and Robustness Studies of Liquid Marbles for Collision-Based Computing

“…Recently, LMs have been shown to be of use in unconventional computing. [6] Such computations result from the collisions of LMs in interaction gates, and the resulting deflected pathways. Using this logic, it is possible to perform mechanical digital Boolean algebra.…”

“…[3,4,5] Depending on the LMs carrier and cargo, LMs can be manipulated using electric and magnetic fields, which makes microfluidic applications of these particles possible. To ensure the LMs work efficiently in these microfluidic devices and as signal carriers in unconventional computing circuits, [6] it is important that the LMs are robust. [7] The interactions between LMs vary depending on their coating and the liquid encapsulated within them.…”

“…It is crucial to understand how the LMs behave under different conditions, with various coatings and encapsulated liquids, to gauge their suitability for use in microfluidic applications and for the purposes of our research, a LM interaction gate for collision-based computing. [6] A collision-based, or dynamical, computation employs mobile compact finite patterns, mobile self-localisations, in active non-linear medium or travelling mechanical devices. [23] There are several sources of collision-based computing.…”

“…Ni particles show magnetic properties and therefore are ideal candidates for devices where non-contact retaining of particles with magnets is required. [35,36,6,37,38] A mixture of Ni and PE was chosen because this coating has proven to be practical in the implementation of collision-based computing devices with LMs. [6]…”

Neuromorphic Liquid Marbles with Aqueous Carbon Nanotube Cores

“…These systems exhibit novel characteristics such as low coefficients of friction [13,14,15], which have been exploited by nature [16,17]. It has been demonstrated that liquid marbles have myriad uses ranging from micro-bioreactors [18,12,19,20] to gas biosensors [21,22] to unconventional computing media [23,24]. Our laboratory has developed LM devices that are capable of implementing computation through a variety of non-standard logics [23,24,25] where the LMs are considered as data or otherwise, to contain data (i.e.…”