The broadest claim of this patent is claim 1:
- A circuit configuration for a capacitive touch switch, the circuit configuration comprising:
at least one sensor circuit containing:
a capacitive sensor element changing its capacitance value when touched;
a capacitor connected in parallel with said capacitive sensor element and defining a parallel circuit;
a capacitance/frequency converter connected to said parallel circuit containing said capacitor and said capacitive sensor element, said capacitance/frequency converter generating and outputting a frequency signal having a frequency being dependent on a total capacitance of said parallel circuit formed of said capacitor and said capacitive sensor element;
said at least one sensor circuit being one of a plurality of sensor circuits outputting output signals and each of said sensor circuits having said capacitive sensor element;
an evaluation circuit receiving the frequency signal being an output signal from said sensor circuit for determining whether said capacitive sensor element is actuated or not; and
a switch connected between said plurality of sensor circuits and said evaluation circuit, the output signals from said plurality of sensor circuits being alternately supplied to said evaluation circuit through said switch.
The instructables circuit does not seem to have a parallel capacitor or a capacitance-to-frequency element. Also the stated theory of operations may not be correct.