Circuit detectors and sensors based electronics projects

A touch sensor switch that works with 10 channels can be built using electronic scheme in the figure below. If you touch one of the 10 sensors, the corresponding output goes in a logical state 1, the other inputs are in logic state 0.
This 10-channel switch is built using 4017 CMOS decimal counter which provides "decoded" signals. A second oscillator realized with CMOS logic gates produces clock signal. The counter is working until it achieved the desired position of the switch.
The switch can be supplied with a DC voltage between 3 and 15 volts DC.

A touch switch sensor can be built using this simple electronic from the figure below. The touch switch sensor is built using a CMOS circuit, a resistor and a capacitor.

A simple touch sensor switch can be achieved using electronic scheme from the figure below. Touch sensor switch from electronic diagram below is built with inverters (N1, N2). In standby state at the entrances of N1 there is a signal produced by oscillator N3/N4. At the touch sensor hand capacity forms a bridge to the ground for the 1MHz signal so that the voltage signal at the entrance of N1 decreases more (at the exit of N2 is logical 1). After the release of contact, a signal charge C4 through D1 Mhz, so the output of N2 is 0 logic after short time.