Now that we know a little about what Arduino and the whole world around us, we can begin to see more closely how the Arduino Uno board is made, a board that we can consider as a basis and reference for all the development on this project. .
If we analyze the board closely we can identify which are the main components that make it up, in the image below we can distinguish a list of main components:
- One USB port (left in image)
- One connector (Jack) for power supply (below)
- the ATmega 328 chip or the microcontroller / brain of our system (large chip in the center)
- a reset button (for restarting the board)
- a small but bright "power on" LED that indicates the power on status of the board
- digital input pin pin connector, to connect add-ons, six of which can be used as pwm signal (more on that later)
- Analog input PIN, to measure signals with various sensors
- PIN Power supply
As we can easily imagine the USB port is used to connect our Arduino board to the computer. Once the Arduino is connected to the PC, we will have the possibility to carry out more operations, for example load a new program (called sketch) on the board, make communications between the Arduino board and the computer to exchange data and finally also power the device. As soon as we connect the board to the PC we can in fact see how it lights up by illuminating the Power ON LED, Arduino is perfectly able to work without the need for additional additional power supplies.
Of course it is not always good to use a whole computer to power a small electronic board like ours (except in cases where communications with the PC are not provided), so if we want to provide an alternative power supply to our project we must connect a 9 volt power supply to the 'special Power Jack.
A 9 volt power supply is ideal for running the arduino, but we can use voltages ranging from 7 to 12 volts. With a power supply of this type we can create circuits that need a power supply greater than the 5 volts provided by the USB port of the computer.
The power supplied to Arduino can be shared with the rest of the circuit that we are going to create on it, this we can do through the power pins that we will find in the appropriate connector, marked with the word POWER, we can see that the pin is available power supply, 5V power supply and also an additional 3.3V power supply for devices powered at this voltage.
To power our circuit from the battery, on the other hand, in addition to the power jack we mentioned earlier with a special 9 volt battery adapter, we can use the Vin and GND pins on the right side of the "power connector", thus making it "mobile" our projects.
At the center of the board we can see our microcontroller (CPU), the Atmega 328, just a little higher and on the right there is the reset button that allows us to reset our system and restart it with a simple press of the button.
Above we can see 14 digital input / output pins, from our program we can configure these pins as an input or as an output according to our needs, we can then read or write their value (which will be ON or OFF).
Using these pins, for example, we can turn on and off a LED, if we have configured it as an output (OUTPU), or read the status of a button in the case of the configuration as an input (INPUT).
In the lower part of the card, on the right we can see the 6 analog input pins. Through these pins we can connect sensors to Arduino that supply variable input voltages depending on the measured value. These values will then be converted by Arduino into a value ranging from 0 to 1024 in order to be able to process them in our sketches.
The assembly of the 14-pin digital I / O connector, plus the 6-pin analog connector is generally referred to as GPIO which stands for General Purpose Input Output or general purpose inputs and outputs.