Arduino
An open-source physical computing platform based on a simple general purpose microcontroller board, and a development environment (Arduino IDE) for writing software for the board. Can be used to develop and implement embedded systems.
Ready to go platform that can be use to simply plug into the computer, upload a program and run it without any additional circuit development.
- Can be used to develop interactive devices, taking inputs from a variety of switches or sensors, and controlling a variety of lights, motors, and other physical outputs.
- Can be stand-alone, or can be run through a software (e.g., Flash, Processing, MaxMSP)
The boards can be assembled by hand or purchased pre-assembled; the open-source IDE can be downloaded for free.
Programming an embedded platform like the Arduino is somewhat different from programming a PC. Unlike the PC, Arduino does not have a keyboard, or a display screen. Moreover, the small amount of memory and storage available is insufficient to host a usable program development environment such as an IDE and a compiler or an interpreter. Hence Arduino programs are usually written and compiled in a different computer (usually a PC) and later downloaded into the Arduino board via the USB cable.
Advantages
- Learning is easy (compared to embedded system development) as it hides messy details of microcontroller programming
- Comes with a lot of hardware facilities ready to use
Hardware
The Arduino board is where the code is executed. The board can only control and respond to electricity, so specific components are attached to the board to enable it to interact with the real world.
These components can be
- sensors - converts some aspect of the physical world to electricity so that the board can sense it. Examples: sensors include switches, accelerometers, and ultrasound distance sensors.
- actuators - gets electricity from the board and converts it into something that changes the world. Examples: lights and LEDs, speakers, motors, and displays.
The most popular boards contain a USB connector that is used to provide power and connectivity for uploading your software onto the board. Figure 4.3 shows the basic components of an Arduino Uno.
The “Mini USB Socket” is used to connect the board to a computer using a standard USB mini cable. This can be used to power the board. The “External Power Input” socket can be used to power the Arduino board with a 6-20V supply.
The “5V Input/Output” pin can be used either to power the board using a 5V supply when there is no other mode of power supplying is used or to get a 5V supply to provide to any other device when some other power supplying mode is in use on the board.
The “Reset Button” can be used to force the board to re-start executing the uploaded program from the very beginning. The “Digital I/O Pins” can be used to provide digital (0 or 5V) outputs and to read digital inputs by configuring them in the program.
Certain pins (3, 5, 6, 9, 10 & 11) are marked with a tilde (~). These pins can be used as PWM (Pule-Width Modulation) outputs. In PWM configuration, these pins can be used to effectively output voltage values in the range 0-5V.
The “Analog Input Pins” can be used either as digital I/O pins or as input pins which can read voltage values in the range 0 – 5V by configuring them in the program.
The “Ground Pins” can be used as ground connections for external circuitry. This is a very basic introduction to the pins and other components of the Arduino Uno board which will be needed in this module.
Software
Software programs for Arudio is created on a computer using Arduino IDE. They are called as sketches. The IDE can be used to write and edit code and convert this code into instructions that Arduino hardware understands. The IDE also transfers those instructions to the Arduino board (a process called uploading).