Debounce

Pushbuttons often generate spurious open/close transitions when pressed, due to mechanical and physical issues: these transitions may be read as multiple presses in a very short time fooling the program. This example demonstrates how to debounce an input, which means checking twice in a short period of time to make sure the pushbutton is definitely pressed. Without debouncing, pressing the button once may cause unpredictable results. This sketch uses the millis() function to keep track of the time passed since the button was pressed.

Step 1: What You Need?

1 x Arduino Board (Arduino UNO used in this tutorial)
1 x 10k ohm resistor
1 x Button / Toggle Switch 

1 x Breadboard
Male-to-Male Jumper Wires 

Optional 
1 x LED(RED)
1 x 220 Ohm Resistor 

Don't have components? Don't worry. Just click the component's name. 

Step 2: Build Your Circuit.

Connect three wires to the board. The first two, red and black, connect to the two long vertical rows on the side of the breadboard to provide access to the 5 volt supply and ground. The third wire goes from digital pin 2 to one leg of the pushbutton. That same leg of the button connects through a pull-down resistor (here 10k ohm) to ground. The other leg of the button connects to the 5 volt supply of Arduino board.

Step 3: Upload The Code.

1. Select the Arduino board type: Select Tools >> Board >> Select your correct Arduino board used.

2.  Find the port number by accessing device manager on Windows. See the section Port (COM&LPT) and look for an open port named "Arduino Uno (COMxx)". If you are using a different board, you will find a name accordingly. What matters is the xx in COMxx part. In my case, it's COM3. So my port number is 3. 

Select the right port: Tools >> Port >> Select the port number.

3. You can find this code in the example of Arduino IDE.
Select File >> Examples >> 02.Digital >> Debounce

Click press the "upload" button (see the button with right arrow mark).

The sketch is based on Limor Fried's version of debounce, but the logic is inverted from her example. In her example, the switch returns LOW when closed, and HIGH when open. Here, the switch returns HIGH when pressed and LOW when not pressed.

Download: 

Arduino software

Sources: [https://www.arduino.cc/en/Tutorial/Debounce]

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Author & Editor

My Robot Education Sdn. Bhd. (Robotedu.my) was founded in 2015 as the first robotics education centre in Malaysia to provide Arduino-based robotics courses for youths. Our vision is to be able to provide robotics education to every youth in Malaysia.