Raspberry Pi Hardware

Here are some pictures of the latest Raspberry Pi 2 Printed Circuit Board (PCB)

In this post we will look at the hardware in detail.

The processing capabilities or brain is provided by the CPU or processor.

In this case it is a a 900 MHz quad-core ARM CPU  (Central Processing Unit)

The 900 MHz represents the clock speed and it represents the number of instructions the CPU can perform in a given amount of time. This clock speed is one benchmark often used to compare CPU's

The quad core means the processing unit has 4 CPU's integrated into the same chip making it even more powerful.

Raspberry Pi  has 1 GB of RAM or Random Access Memory. RAM is like a blackboard or scratch pad which the CPU uses to load temporary programs and values. For example if the CPU were adding two numbers , it would use some location in memory to store the numbers and add them up and finally store the answer back in some location

But RAM is not meant for permanent storage. It only acts as temporary buffer space . RAM is volatile i.e; the contents will be lost once the PC is switched off.

For permanent storage , traditionally we use Hard Disk Drives. In case of the pi we use a SD Card (Secure Digital Card) to store information or data permanently. You may have seen SD Cards in Digital Cameras. Their is a Micro SD card slot on the Pi. Here you can insert a SD card. A 4 GB SD card can be used but a minimum of 8 GB SD card is recommended.

We need a keyboard and a mouse for input. On his version 2 of the Pi their are 4 USB ports.

We can connect a USB Keyboard and USB mouse using these USB ports. You can connect a USB WiFi adapter. This gives us wireless access to the Network/Internet.

To save space and less clutter you can buy a cheap wireless keyboard and mouse combo unit

In earlier models of the pi there were only 2 USB ports and two connect more than two USB devices we have to use a powered USB Hub to get more USB ports. This newer pi version has 4 ports and solves that problem.

It has one HDMI port. This HDMI output port allows us to connect to a HDMI TV or monitor and see what is happening on our PC made with this Raspberry Pi.

HDMI stands for High-Definition Multimedia Interface. All the new TVs and Monitors do have a HDMI port. You can connect the Raspberry Pi to a HDMI TV using a HDMI Cable.

It has a Ethernet port to connect the Pi to the network using a network cable. Generally we would connect one end of the Network cable to the Pi Ethernet port and connect the other end to a Ethernet port on your service providers modem or router.

However as mentioned , we can go the wireless way by connecting a USB WiFi adapter

Their is a Micro USB Power Source to power the Pi. The power source is like the one we use to charge our smart phones. It is recommended to use a power source or adapter that is made exclusively for the Pi rather that the cell phone charger due to current ratings.

It has a combined 3.5mm audio jack and composite video for connecting to speakers for audio and video output for older TVs

Their is a camera Interface to connect a camera and a display interface to connect a LCD display unit.

One important thing that is unique to Raspberry Pi are the GPIO pins, which is a dream come true for everyone interested in electronics. GPIO stands for General Purpose Input Output pins. As the name suggests these are Input Output pins. You can configure programatically what a pin does. Does it receive input or does it send out some output. For example you could connect a LED and control from a program when a output signal is sent to light up the LED. A GPIO pin could be programmed as a input pin and could trigger some action when input is received from a switch or any other device.


To summarize we need the following to build your personal PC using the Raspberry Pi:

1. Raspberry Pi. Look for the Pi Board that has a high clock speed and with multiple processors or core. Raspberry Pi 2 is the latest and greatest that is currently available.
2. Micro USB Power adapter to power the pi. A android phone adapter will fit but it is recommended to use a adapter that has been built for the pi due to current implications.
3. USB Keyboard and USB mouse. You could use wired or wireless input devices. Recommend using a keyboard and mouse combo unit with wireless capability
4. For output to see what's happening on the pi, we need a TV or Monitor that have a HDMI port.
5. Also need a HDMI Cable to connect the Pi to your TV.
6. For network connectivity using a cable or wire need a network cable. Make the network connectivity wireless by using a USB Wireless adapter
7. For loading the operating system and other software we need a Micro SD card. 8 GB is recommended and it is goo to have a couple of SD cards.
8. Speaker Set for sound output. If your TV set is able to give good sound output then you won't need the speaker set as the HDMI cable sends both audio and video from the Pi to the TV.

Other things that are useful

• A Case to protect the Pi. I like a transparent case as we can see the the circuit board . It is more about the visual appeal and appreciating the engineering and human ingenuity in building this compact circuit board.
• To load all the programs on to the Pi we need a PC or MAC that has a SD card slot.

Some other things which are not needed but make it more interesting are:

• A pi camera that provides you the capability to take pictures and videos which is useful in many projects
• A LCD touch screen panel for the Pi to have a display of its own.

The unique capability of the Pi is in the electronic projects that you can do with the Pi using the GPIO pins. Once you are ready to do electronic projects you will need electronic components like resistors, switches, transistors, capacitors, bread board etc. We will discuss this in detail in subsequent articles.

Electronic projects are done by many people using the very popular Audrino kits. The Pi adds the capability of not only creating electronic projects but also increased programming capability like for example sending out alerts and logs out. Google on Audrino to find out more about it.

Last but not the least we need your brilliant and inquisitive mind to build , use , learn and play with this PC that you will build.

 This Shows the Front of the Pi Board.

This shows the back of the Pi Board

This picture shows the different ports on the Side

This picture shows the ports available on the other side