Autonomous agents, whether in the air or on the ground, require precise information about their surroundings for safe navigation. Laser scanners, also referred to as LIDAR (LIght Detection And Ranging), perform particularly well in building accurate virtual models of the surroundings and are relatively insensitive to varying environmental conditions. However, commercially available laser scanners are very expensive, which inhibits their widespread use. This work proposes a design for a low-cost LIDAR system, comprising an optical setup, an electronics system, a controller, and required software for processing the measurements. The ultimate goal is to construct a laser scanner which is suitable for environment scanning and obstacle identification on Unmanned Aerial Vehicles (UAV), commonly referred to as drones. Throughout the process care is taken to keep the complexity low and to rely only on readily available components. In order to assert the validity of the proposed design a prototype is built. An extensive evaluation quantifies the performance of the laser scanner in terms of range, precision, spatial resolution, and scan rate.