Acoustic Measurements with a Quadcopter: Embedded System Implementations for Recording Audio from Above

Abstract

At present, making audio recording requires an investment of time and energy. Microphones must be setup, connected to amplifiers and filters, and then passed into a computer s sound card. If the micro-phone is not positioned properly, someone must manually move the microphone stand and re-test the audio. If multiple measurements are needed from around a room, a significant portion of time will be spent just moving the microphone and cables. An automated method of moving the microphone around the room is often desired and this thesis lays out the option of using a quadcopter to facilitate this work.Explored here are two different embedded systems that are capable of making measurements from a hovering quadcopter. The first is a rapidly developed design using an Apple iPod Touch. While the recording quality and the ease-of-use of the iPod are very high, the system does not offer any low-level OS control, resulting in unpredictable delays when synchronizing to the loudspeaker setup. However, this system does allow for making significant measurements of quadcopter noise and stabil-ity, which prove valuable for future designs. The second design seeks to improve upon the synchroni-zation issue. Built using two Atmel SAM4L Xplained Pro development boards, the system achieves a sample accurate synchronization between the quadcopter and loudspeaker systems.The final conclusions combine the results from both systems. Recommendations for future iterations of the SAM4L design are discussed. Suggestions for the SAM4L design include improving audio re-cording quality, reducing the amount of noise the quadcopter generates, and multiple methods for can-celling noise that is recorded by the microphone.