Figure 1: Raspberry Pi 2 Model B

Raspberry Pi is a small credit card sized computer, It is very cheap compared to the traditional computers, the Raspberry Pi Foundation has arrangements with a few manufacturers from whom you can buy a Pi directly at $25 – $35.

This small computer was developed with an intention of teaching computer programming to school students. It is developed in United Kingdom (UK) by Raspberry Pi foundation which is a registered charity.

You can do many things with this Pi, there’s no single way to use it. Just like a normal PC, you can watch videos, play games, surf the internet, there are a wide variety of free software that you can install for working with documents and spreadsheets.

As the Raspberry Pi is meant as an educational tool to encourage kids to experiment with computers, it comes pre-loaded with interpreters and compilers for many different programming languages. If you run it with Linux operating system, there’s Scratch, a graphical programming language, There is Python programming language that you can start with to write your codes. You can also write programs for your Raspberry Pi in many different programming languages like C, Ruby, Java, and Perl.

The Raspberry Pi unlike the traditional computer, it has the ability to integrate with electronics projects. This is where our main focus will be in this Raspberry Pi tutorial and project series. Even though you can also use a Raspberry Pi to control devices that a microcontroller can control like LEDs, relays, LCDs etc. A Raspberry Pi is better used where more processing power and connectivity is needed like for exemple when you want to remotely access a temperature sensor via the web to change its settings and download temperature log files and more in general Internet of Things (IoT) and Home Automation applications you should consider using the Raspberry Pi.

Raspberry Models  

The raspberry Pi models can confuse new comers, there are few importants things you should know before choosing the correct board for your application:

  • Power consumption: This is one of the deciding factor. If your application is battery powered such as a data logger in a remote location, then power consumption becomes a critical factor. The A Models require less power than the B Models.
  • Cost: The model A is priced at $25 while the model B is $35.
  • Peripherals: The main advantage of the Model B is its networking capability. Model A does not have an Ethernet port and has only one USB port while the model B has Ethernet port and four USB ports. The new Pi 3 model B has integrated 802.11n wireless LAN, and Bluetooth 4.1

Raspberry Pi 1 Model A

Model A is the lower-spec variant of the Raspberry Pi, the first Raspberry Pi 1 model A as shown on figure 2 below has 26 General Purpose Input/ Output pins (GPIO), 256 MB of RAM, one USB port and no Ethernet port.

Figure 2: Raspberry Pi Model A

The newer Model A+ replaced the original Model A in November 2014. Compared to the Model A it has:

  • More GPIO: The GPIO header has grown to 40 pins, while retaining the same pinout for the first 26 pins as the Model A and B.
  • Micro SD: The old friction-fit SD card socket has been replaced with a much nicer push-push micro SD version.
  • Lower power consumption: By replacing linear regulators with switching ones they’ve reduced power consumption by between 0.5W and 1W.
  • Better audio: The audio circuit incorporates a dedicated low-noise power supply.
  • Smaller, neater form factor: They’ve aligned the USB connector with the board edge, moved composite video onto the 3.5mm jack, and added four squarely-placed mounting holes. Model A+ is approximately 2cm shorter than the Model A.

Figure 3: Raspberry Pi Model A+

The Model A+ is recommended for for embedded projects and projects which require very low power, and which do not require Ethernet or multiple USB ports.

Raspberry Pi Zero

The Raspberry Pi Zero is half the size of a Model A+, with twice the utility. It’s really a tiny Raspberry Pi that’s affordable enough for any project!

  • 1Ghz, Single-core CPU
  • 512MB RAM
  • Mini HDMI and USB On-The-Go ports
  • Micro USB power
  • HAT-compatible 40-pin header
  • Composite video and reset headers

Figure 4: Raspberry Pi Zero

Raspberry Pi 2 Model B

The Raspberry Pi 2 Model B is the second generation Raspberry Pi. It replaced the original Raspberry Pi 1 Model B+ in February 2015 Figure 1 above shows a Raspberry pi 2 Model B. Compared to the Raspberry Pi 1 it has:

  • 900MHz quad-core ARM Cortex-A7 CPU
  • 1GB RAM

And also like the (Pi 1) Model B+, it has:

  • 4 USB ports
  • 40 GPIO pins
  • Full HDMI port
  • Ethernet port
  • Combined 3.5mm audio jack and composite video
  • Camera interface (CSI)
  • Display interface (DSI)
  • Micro SD card slot
  • VideoCore IV 3D graphics core

Figure 5: Raspberry pi 2 Model B description

Because it has an ARMv7 processor, it can run the full range of ARM GNU/Linux distributions, including Snappy Ubuntu Core, as well as Microsoft Windows 10 IoT core which is free of charge to makers. This board is ideal for Internet of Things (IoT) and Home Automation applications

Raspberry Pi 3 Model B

The Raspberry Pi 3 is the third generation Raspberry Pi. It replaced the Raspberry Pi 2 Model B in February 2016. Compared to the Raspberry Pi 2 it has:

  • 1.2GHz 64-bit quad-core ARMv8 CPU
  • 802.11n Wireless LAN
  • Bluetooth 4.1
  • Bluetooth Low Energy (BLE)

Like the Pi 2, it also has:

  • 4 USB ports
  • 40 GPIO pins
  • Full HDMI port
  • Ethernet port
  • Combined 3.5mm audio jack and composite video
  • Camera interface (CSI)
  • Display interface (DSI)
  • Micro SD card slot (now push-pull rather than push-push)
  • VideoCore IV 3D graphics core

Figure 6: Raspberry pi 3 Model B

This board is completely compatible with Raspberry Pi 1 and 2.