Connecting an arduino button is a basic electronics skill that’s easy to learn. It’s also a great way to get your hands dirty with a microcontroller.
You’ll need an Arduino Uno or MEGA 2560, a breadboard, a push button switch, and an LED. The next step is to load a sketch that will control the behavior of the button and LED.
The Button example sketch comes with the Arduino IDE and is available from the arduino website. It’s a simple program that checks whether the button is pressed, and if it is, turns on the LED.
First, you’ll need to set up the pins on the board. This can be done by using the setup() function. The first call to this function will set up the push button switch, and the second will set up the on-board LED. This code is repeated twice, so make sure to have the LED connected to pin 13 and the push button switch connected to pin 2.
Once these items are configured, you can add them to the Button example sketch. This will ensure that they are accessible when you are programming the circuit.
You will need to wire the button to the pin and the resistor to the ground bus on the breadboard. You’ll also need to attach a jumper wire to one of the button’s pins and another jumper wire to the 5 volt pin on the board.
To do this, use the digitalRead() function to read the value of the pin you’ve defined as buttonPin in the setup() function. The value will be either HIGH or LOW, depending on whether the button is pressed. The digitalRead function will also save this state into a variable called buttonState, which you can use later to control the behavior of the sketch.
If the button is pressed, digitalRead will send 5 volts to the buttonPin, causing the value of the buttonState variable to change from LOW to HIGH. This is the same voltage that will be used to power the on-board LED.
Pull-Up Resistors
When you use an input pin to read a voltage, it’s best to connect a resistor between the pin and ground. This will prevent stray electromagnetic energy from escaping through the wires and damaging your circuit.
You can use a pull-up resistor in place of a pull-down resistor, but you must be sure to use the INPUT_PULLUP mode on the input pin. This will force the default reading voltage to be 5V – LOW, as opposed to the floating voltage that can occur without the resistor.
If you don’t add a resistor, the value may end up “floating” between 0V and 5V, which will give you erratic results when the button is pressed or not pressed. This can cause problems with the program and can make it hard to understand how the code is responding to the button press.
