Evolution of astable multivibrators in Silico

We use evolutionary search to find automatically electronic circuits that toggle an output line at, or close to, a given target frequency. Reconfigurable hardware in the form of field-programmable gate arrays-as opposed to circuit simulation-computes the fitness of a circuit which guides the evolutionary search. We find empirically that oscillating circuits can be evolved that closely approximate some of the supplied target frequencies. Our evolved oscillators alias a harmonic of the target frequency to satisfy the fitness goal. Frequencies of the evolved oscillators were sensitive to temperature and to the physical piece of silicon in which they operate. We posit that such sensitivities may have negative implications for demanding applications of reconfigurable hardware and positive implications for adaptive computing.