There are multiple types of Arduino boards intended for different purposes. Despite having some varying components on each board, these features are usually consistent across all types of Arduino boards:
USB/Barrel Jack
Every Arduino board needs access to power. This can be achieved through a USB cable connected from your computer to the board, or a power supply from the wall. In the above image, the USB port is labelled as (1), and the barrel jack (for wall power supply) is labelled as (2). An Arduino board is only capable of receiving power at a rate less than 20 volts. Any power supply higher than that can overpower and destroy the Arduino board. The recommended amount of power is between 6 and 12 volts. For loading code onto the Arduino board, the method to use is via USB cable.
Pins
Pins allow wires to be connected to the board to build circuits, usually used in conjunction with a breadboard and wire. The pins have black plastic ‘headers’ to enable the wires to slot right into the board. An Arduino board has a variety of pins, situated around the edges, which you can see in the image above labelled 3-9. These are:
- GND (Ground) - An Arduino has multiple GND pins (3), which are used to ground the circuit. A circuit is grounded when one of the conductive wires which is connected to the circuit is intentionally given a direct route to the Earth
- 5V (4) & 3.3V (5) - These pins are straightforward. One supplies 3.3V of power, and the other supplies five. Most components on an Arduino can run off either amount of power
- Analog (6) - You can see these pins in the above image, underneath the ‘analog in’ section. These pins can read the signal from an analog sensor and convert it into a readable digital figure
- Digital (7) - On the opposite side of the board, you can see the digital pins (0-13). These can be used for digital input and output
- PWM (8) - Some of the digital pins have a ‘~’ symbol next to them in the image above. These pins can be used for regular digital usage, but also have the power to be used for Pulse-Width Modulation (PWM). PWM is a method for achieving analog results with digital means
- AREF (9) - This refers to Analog Reference. A lot of the time, this isn’t used, but it can be used to set an external reference voltage as the maximum power for analog input pins
Pushing the reset button (10) temporarily connects the reset pin to ground and restarts any code that’s loaded onto the Arduino.
LED Power Indicator
Situated next to where it says ‘ON’ in the above image is an LED light. This should light up when the Arduino is connected to a power source and indicates that the board has power.
TX RX LEDs
TX (transmit) and RX (receive) indicate pins which enable serial communication. These signs are seen in the above image twice, next to digital pins 0 and 1 and then also by the TX and RX LED indicators (12). These LED indicators show when the Arduino is transmitting and receiving data.
Main IC
Short for integrated circuit, and can be seen in the above image (13). This is essentially the brain of the Arduino PCB. The ICs can vary from board to board, but it’s important that you know which one you’re using, as it will be a key piece of knowledge for loading a new program onto the board with the Arduino software. The type of IC is usually indicated on its surface.
Voltage Regulator
The voltage regulator (14) is important for maintaining the right amount of power being circulated through the board. It essentially turns away any excess power in order not to damage the Arduino. However, this is within reason and doesn’t mean you can connect it to any power source. The maximum should be 20 volts.
