OptiSens - Convex optimization of sensor and actuator placement for ultrasonic guided-wave based structural health monitoring. This paper presents OptiSens, a computational platform in Python and Matlab, that provides optimal sensor and actuator configurations for structural health monitoring applications using ultrasonic guided-waves. This software formulates a convex entropy-based objective function, which aims at minimizing the uncertainty while maximizing the expected accuracy of the monitoring system in localizing structural damage. The platform is specialized for two types of different materials, namely isotropic and composite (anisotropic) materials. The effectiveness and efficiency of this software are demonstrated using two plate-like structures made of different materials.