A customizable, low-cost alternative for distributed 2D flow sensing in swarms

Many collective behaviors in social insects are mediated by airflow, such as honeybees fanning their wings to drive nest ventilation or to disperse pheromones during olfactory search and aggregation. Empirical investigations of how the local sensing and actuation of individual insects scale up to produce such large scale flows require distributed flow measurement techniques. Common vision-based techniques, however, are not workable in the cluttered dynamic environments in which these social insects live and behave. Here, we developed a customizable, low-cost 2D flow sensor that can measure both magnitude and direction and be deployed in dense sensor arrays on experimental surfaces. While many 2D thermal flow sensor designs have been published, our minimal design uses off-the-shelf components and standard fabrication techniques that should be accessible to most research groups. Here we report on the design and performance of our sensor and provide a user-friendly calibration protocol. The sensor has a measurement range of 0–2 m/s with accuracy of 0.1 m/s, angular resolution of \(15^\circ\), and a time constant of 3 s. We also discuss modifications that can be made to tune sensor performance for a given application.