Many research and teaching laboratories rely on USB data acquisition devices to collect voltage signals from instrumentation. However, these devices can be cost-prohibitive (especially when large numbers are needed for teaching laboratories) and require software to be developed for operation. In this article, we describe the development and use of an open-source USB data acquisition device (with 16-bit acquisition resolution) built using simple electronic components and an Arduino Uno that costs under $50. Additionally, open-source software written in Python is included so that data can be acquired using nearly any PC or Mac computer with a simple USB connection. Use of the device was demonstrated for a sophomore-level analytical experiment using gas chromatography and a capillary electrophoresis-UV separation on an instrument used for research purposes.