A low‐cost, highly flexible, open‐source setup design with digital LEDs for research on artificial light at night

Artificial light at night (ALAN) is a global change factor of growing relevance, yet its impact on organisms remains poorly understood. Present studies point to rather negative impacts of ALAN on species and ecosystems. Most research on ALAN uses conventional LED technology without simulating the complex spatial and temporal facets of ALAN. However, to fully explore and understand the potential consequences of ALAN on organisms, research equipment must be able to mirror environmental light (pollution) scenarios more realistically. To expand research possibilities on ALAN, we designed a highly flexible research setup with digital LEDs controlled by an Arduino with open‐source programming. For different light intensity levels, we tested the homogeneity of illuminance across the LEDs in a setup with numerous replicate compartments. The standard deviation of the mean illuminance across individual LEDs ranged between 2.8% and 9.5%, depending on the light intensity level, whereas conventional LED setups show a variation of up to 30%. Thus, our setup can achieve a high comparability amongst replicates that can be tested in randomised block designs. Our LED setup offers a novel technical approach for conducting a wide range of research involving light as a cue. We provide detailed descriptions of the construction, information on common pitfalls, and suggest components for adjustment. Thus, this setup can easily be rebuilt and adapted to fit the specific research needs.