Any conductive surface can be turned into a sensor plane by measuring the increase in its capacitance brought about by conductive objects approaching the layer. Depending on the size, material and distance of the objects to detect, this capacitance measurement can become quite difficult as electrical perturbations in the sensor's vicinity may overshadow the usable signal. In our tutorial we present an efficient measurement hardware and appropriate filter algorithms to account for this challenge. The result is a self-calibrating sensor board, which can measure up to eight different sensor surfaces independently in real time. This offers a unique platform for creating interactive environments.