Arduino Boards
Arduino boards are microcontrollers with connectors for sensors, controllers, and display components, everything that is required to build physical computing or IoT solutions.
While specifications vary across boards, they all generally have the following:
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A microcontroller:
This executes the instructions (in the Arduino world they are referred to as sketches) that tell the board what it needs to do. The microcontrollers come with varying amounts of flash memory (the equivalent of ROM).
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Serial communications interfaces:
Arduino boards need to be connected to a computer to upload programs using the Arduino IDE. They also get their power from the computer. Once the program is uploaded, it can be connected to an independent power supply and eliminates the need for computers. The connecting cables for Arduino boards are all variants of USB connectors. The computer or power supply side is the most commonly used USB Type-A connector. The board side uses either USB Type-B, Mini-USB, or Micro-USB.
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Digital and analog input/output (I/O) pins
The boards are equipped with sets of pins that can be connected using wires to components or other boards or modules.
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A 5V or a 3.3V linear regulator
Arduino boards can be powered from your computer or with a DC supply or batteries. The onboard regulator maintains the voltage at the required level to prevent damage to the board.
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USB Cable Connector
This is to allow the board to be connected to a computer from where the program can be uploaded to the Arduino board. One important aspect of USB cables is that they are for charging only or for charging and data. For programming Arduino and other boards, you need cables that support charging and data. Data cables have four connector wires in the USB interface, while power cables have only two connector wires. It is not easy to differentiate between the two visually, so you must read the specifications thoroughly.
Arduino microcontrollers are pre-programmed with a boot loader that simplifies the uploading of programs to the on-chip flash memory. Boards are loaded with program code via a serial connection to another computer.
Arduino UNO
The most commonly used Arduino boards for learning or hobby projects are the Arduino Uno and the Arduino Nano. The image below shows an Arduino UNO and all its onboard pins and components.
Compatible Boards
Arduino is an open-source project, which means that its circuit designs are available for anyone to use, even for commercial purposes. While Arduino makes and sells original boards, many other manufacturers make boards with the same design and are compatible with all Arduino boards, shields, accessories, and software. You can choose to buy an original Arduino board, which comes with the reliability you can expect from an original product, or buy a compatible board, which is usually good but you may experience issues in some cases.
Arduino Ecosystem
Arduino is an open-source platform that simplifies the task of building electronic circuits, and more specifically physical computing or IoT solutions. The platform includes hardware (known as Arduino Boards) and software (known as the Arduino Integrated Development Environment).
Arduino boards are designed such that it is easy to connect sensors to them. The boards read inputs from connected sensors and can be programmed using the IDE and the Arduino programming language to process the inputs. It is also easy to connect output devices (such as LEDs and relays) to Arduino boards and have the programs control them.
The Arduino platform was created as an easy tool for fast prototyping without requiring too much knowledge of electronics and programming, aimed at students and enthusiasts. The main objective is to make the process of working with technology and electronics easier.
There are other similar projects, but Arduino is the most popular, as it is easy to use and inexpensive. The Arduino platform is evolving and while it remains easy to use for beginners it is also mature and powerful enough to use in advanced solutions.
Arduino Modules
While all Arduino boards offer basic processing and input/output connectors for sensors, relays, and display components, some boards may not offer advanced options, such as the ability to connect to a WiFi network or receive Bluetooth signals. Modules are specialised circuits that are designed to work with Arduino boards to provide these additional features that the Arduino boards may not have. Modules are separate circuits and need to be connected to the primary board using wires and connectors.
**Shields **
Shields are an alternative to modules. Shields are designed to augment the functionality of boards just like modules, but they are designed in a manner that they can be plugged into the primary Arduino board. The size of a shield is the same as the primary board and aligned with the necessary pins, which allows the rest of the connectors or pins of the primary board to be accessible through the shield. Shields are available for use with Arduino UNOs but not for other boards.
This design approach allows you to buy smaller and less expensive boards and augment their features as required rather than always needing to buy a full-featured board, which will be more expensive and take up space. As technology evolves and the cost of production goes down, Arduino boards may start to include more features for the same price and in the identical size of the board, in which case some shields and modules may no longer be required.
Some of the more commonly used modules are WiFi Modules, Bluetooth Modules, and Radio Modules.