Our project idea developed through collaboration with the company Philips. The firm needs a method to confirm a skin contact. This should proceed galvanically isolated and electromagnetic compatible. So we decided us together for a solution with capacitive touch-sensors. A comprehensive comparison has shown us that the m-Touch system from Microchip with the PIC 19f1936 is the best way to solve this task. We display the touch with LED’s because we were called upon to do so. The error-checking code is too complex for us so we got a nucleus provided from Microchip. The assignment from that point was to adjust the subtleties and create a table with the parameter settings at accumulator- and grid operation.
For more information about the measuring system click the following link: cvd-system.
We built up our first prototype (pictures: links on the left side) after the basic conditions was set. Phillips also constructed a system with the measuring system from Analog as a result we got a case for our prototype. The touch-surfaces are only four copper-faced areas on a board. Furthermore the system was built up that it is supplied by accumulator and a step up converter. This is necessary because we have to determine the differences between accumulator- and grid operation. For the grid supply we only have to connect the ground and the energy is still provided from the accumulator.