Button press counter (Serial output)

Objective

Count the rising edges of a push button on pin 2 and print the running total on the Serial monitor.

Procedure

1. Press Start Simulation and open the Serial tab: count=1 … count=4.
2. Change the button's press pattern to add more presses.

Theory

Edge detection: a press is counted when the pin changes from LOW to HIGH, not while it stays HIGH. The button pattern 0101010100 at 0.5 s steps gives four presses.

Questions to answer

1. What happens if the contact bounces?

Components used

Arduino UNO R3 (clone, SMD), Breadboard 400 points, LED 5mm Red, Push Button tactile 6x6, 2 × Resistor 220 ohm 1/4W

About the model

Breadboard contacts are ideal (no contact resistance or capacitance). Arduino-style C/C++ subset interpreter (not AVR machine code): no interrupts or libraries, int is 16-bit, only delay() advances time, pin modes are fixed after setup(). Outputs are 5 V behind 25 Ω.

More Microcontroller Lab experiments

• Light-controlled lamp (LDR + analogRead)
• PWM fade (analogWrite ramp)
• LED chaser (for loop over pins)