Normal Close Switches
Normal-Close basically means in the normal state of the switch i.e non-pressed state, the switch is a closed circuit.The circuit breaks when the switch is pressed.
Assuming we connect a normally closed switch to an LED the way we usually connect our switches i.e. one leg of the switch to the GND and the other leg of the switch to the to the output device, we will realize that the LED light will turn on when the switch is idle and turn off when the switch is pressed. This is the behavior of Normal-Close switch. See the circuit diagram and example source code’s link below. To learn about Normal-Open switches, please see this lesson.
Connecting a Normal Close switch to a microcontroller
- Enable the clock of the GPIO pin
- Set GPIO pin as input
- Enable internal Pull-up resistor for GPIO pin