Copyright © 2019 Association of Computing Machinery. Mutual capacitance-based multi-touch sensing is now a ubiquitous and high-fidelity input technology. However, due to the complexity of electrical and signal processing requirements, it remains very challenging to create interface prototypes with custom-designed multi-touch input surfaces. In this paper, we introduce Multi-Touch Kit, a technique enabling electronics novices to rapidly prototype customized capacitive multi-touch sensors. In contrast to existing techniques, it works with a commodity microcontroller and open-source software and does not require any specialized hardware. Evaluation results show that our approach enables multi-touch sensors with a high spatial and temporal reso...