Arduino

What is an Arduino? 

The Arduino is the board shown in the figure below

Basically, it is a small development board with a brain (also known as a microcontroller) that you can connect to electrical circuits. This makes it easy to read inputs – read data from the outside – and control outputs - send a command to the outside. The brain of this board (Arduino Uno) is an ATmega328p chip where you can store your programs that will tell your Arduino what to do.

Exploring the Arduino Uno Board 

In the figure above you can see an Arduino board labeled. Let’s see what each part does.

 Microcontroller: the ATmega328p is the Arduino brain. Everything on the Arduino board is meant to support this microcontroller. This is where you store your programs to tell the Arduino what to do.

 

 Digital pins: Arduino has 14 digital pins, labeled from 0 to 13 that can act as inputs or outputs.

# When set as inputs, these pins can read voltage. They can only read two states: HIGH or LOW. 

# When set as outputs, these pins can apply voltage. They can only apply 5V (HIGH) or 0V (LOW).

 PWM pins: These are digital pins marked with a ~ (pins 11, 10, 9, 6, 5 and 3). PWM stands for “pulse width modulation” and allows the digital pins output “fake” varying amounts of voltage. You’ll learn more about PWM later.

 TX and RX pins: digital pins 0 and 1. The T stands for “transmit” and the R for “receive”. The Arduino uses these pins to communicate with other electronics via Serial. Arduino also uses these pins to communicate with your computer when uploading new code. Avoid using these pins for other tasks other than serial communication, unless you’re running out of pins. 

 LED attached to digital pin 13: This is useful for an easy debugging of the Arduino sketches. 

 TX and RX LEDs: these leds blink when there are information being sent between the computer and the Arduino. 

 Analog pins: the analog pins are labeled from A0 to A5 and are often used to read analog sensors. They can read different amounts of voltage between 0 and 5V. Additionally, they can also be used as digital output/input pins like the digital pins.

 

 Power pins: the Arduino provides 3.3V or 5V through these pins. This is really useful since most components require 3.3V or 5V to operate. The pins labelled as “GND” are the ground pins. 

 Reset button: when you press that button, the program that is currently being run in your Arduino restarts. You also have a Reset pin next to the power pins that acts as reset button. When you apply a small voltage to that pin, it will reset the Arduino. 

 Power ON LED: will be on since power is applied to the Arduino. 

 USB jack: you need a male USB A to male USB B cable (shown in figure below) to upload programs from your computer to your Arduino board. This cable also powers your Arduino. 

 Power jack: you can power the Arduino through the power jack. The recommended input voltage is 7V to 12V. There are several ways to power up your Arduino: rechargeable batteries, disposable batteries, wall-warts and solar panel.