According to an aspect, a method includes detecting, by a computing system, whether there are any pre-existing objects between a first group of sensors of a sensor array in an elevator shaft. The computing system detects whether there is a foreign object between a second group of sensors of the sensor array in the elevator shaft, where the second group of sensors includes at least one sensor that differs from the first group of sensors. The computing system triggers a modification to a control aspect of an elevator car in the elevator shaft based on detection of the foreign object.