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An array of pulse-emitting oscillators capable of emerging collective behavior is investigated by computer simulations and through a simple experimental setup. The oscillators emit pulse-like signals and detect the signal emitted by the others. They have stochastically fluctuating periods and can operate in two different modes, one with a short output pulse and one with a longer one. The switching between modes is governed by a simple optimization rule: whenever the total output in the system is lower than a desired f * threshold level they emit long pulses and when the output is higher than f * they emit short-length pulses. This simple dynamical rule optimizes the average output level in the system around the f * value and acts as a coupling between the units. As a side-effect of this simple dynamics complex collective behavior appears. In spite of the fact that there is no direct phase-minimizing interaction between the units, for a certain f * interval the pulses of the oscillators synchronize. Synchronization appears and disappears abruptly as a function of the f * threshold parameter, suggesting a dynamic phase-transition. In the synchronized phase the collective output of the system has a better periodicity than the oscillators individually. A simple experimental setup with flashing multimode oscillators is built. For a given range of the threshold parameter the experimental setup reproduces the theoretically predicted synchronization.

A system of flashing electronic oscillators exhibiting highly nontrivial synchronization is built and studied. The electronic oscillators are capable of detecting the ambient light intensity and for emitting light pulses in various modes. A simple optimization rule drives the system. Whenever the light intensity detected by an oscillator is lower than a critical * value, the oscillator chooses an operation mode that increases the ambient light intensity. In contrary, when the light intensity detected by the oscillator is smaller than * the oscillators operate in a mode that decreases the ambient light intensity. As a result of this simple optimization rule an unexpected synchronization of the emitted pulses appears for a given * interval. Our experimental results confirm the earlier computer simulation predictions.

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