dandel.io - Design of an audio-recorder accessory

Modern smart-phones and tablets offer considerable computing power to make them viable for a multitude of different tasks. Especially their small form factor makes them appealing when mobility or ad-hoc functionality is a desirable asset. Add-on devices (a.k.a. accessories) provide additional interfaces enabling even more advanced applications that require otherwise elaborate equipment. This paper describes a student project where we developed an audio-recorder accessory for devices running either iOS or Android. In particular, the paper details the hardware and software design of the embedded system as well as implementation details that need to be considered when designing a respective app for both the Android and iOS ecosystems, respectively.