Capacitive touch sensing monitors the capacitance of an element and identifies a change in capacitance between the ‘touched’ and ‘untouched’ capacitance. In most cases the interaction is with a conductive object (finger or stylus) which impacts capacitor C3 and capacitor C4, as shown here, as well as the coupling to ground. Additionally, in applications that do not involve a conductive object or the conductive object is kept relatively far away from the sensor, the change in capacitance of C2 can be monitored as the dielectric changes. The figure highlights the parasitic capacitance between an electrode and surrounding structures. In simplest terms capacitive touch sensing is the sensing of a change in capacitance. This change in capacitance can be caused by the introduction of a conductive object, introducing parasitic capacitance C3 and C4 as well as coupling to ground. A change in capacitance can also be caused by the dielectric changing, causing capacitance C2 to increase (assuming the air is displaced with another material). This presentation will look at how the MSP430 can be used to measure or sense these types of changes in capacitance.