The $35 Raspberry Pi is a credit-card-size computer developed with the intention of promoting computer science. It is a pleasant exodus from the monotonous computing world. Here is how you can get your Raspberry Pi up and running
Most computer science students get to learn high-level programming languages and application development but they don't really understand computers. The fun of controlling the real world with a real computer is never exposed to them.
A normal computer lacks the capability to communicate with the real world through real interfaces.
With a normal computer that has a monitor, keyboard, mouse, printer and modem connected, hardly anything can be done, except the intended use. Of course, the printer port on a PC can be used to interface with the real world but that will be very clumsy and cumbersome-not to talk of the non-availability of an easy programming environment for that.
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The Raspberry Pi is a pleasant exodus from that monotonous computing world. You can hold this palm-size computer in your hand and at the same time interface with the real world with its 26 input/output (I/O) pins. With a Raspberry Pi in hand, robotics is no more a fancy imaginary world of big and serious people but a real and authentic one.
You can get this computer for a small amount of money. In the UK, the Raspberry Pi Model-A costs $25, while the price of Model-B is $35, plus local taxes and shipping/handling fees. In India, at many hobby outlets, it is available for only Rs 2600. In fact, the latest B Model with 512MB RAM is no less than a Celeron computer of yesteryear, yet with a whole lot of imagination and possibilities to tap.
Model-A and Model-B The first model of Raspberry Pi that appeared was Model-A, which had only one USB port and no Ethernet socket. Later, Model-B came into market with two USB ports, Ethernet socket and 256MB RAM. The latest one has as much as 512MB RAM. It is built around a BCM2835 Broadcom processor. It consumes 5V electricity at 1A current. As power consumption is less, there is no heat dissipation and no clumsy heat-sink is required. The operating system is based on the light-weight ARMv6 instruction set that a typical Broadcom processor understands-all open source and based on Linux variety.
Wiring it up Connect the peripherals as shown in Fig. 1.
Video cable connection. Unfortunately, the normal PC monitor-a VGA monitor-does not support connectivity with Raspberry Pi. The Raspberry Pi team, in fact, has thought beyond this and provided the latest and oldest connectivity for video.
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The VGA technology is old and the last of its kind. It is fast being replaced with DVI or HDMI. However, almost every TV-old or new-has an audio/video input socket at its back for connectivity with a VCP, VCR, gaming console, etc. Connect one end of an AV cable to this TV video input port and the other end to the yellow 'TV video output' on Raspberry Pi. The monitor is ready now. There is also a display serial interface (DSI) output for connecting to a flat-panel display or tablet. The latest TVs (plasma, LCD and LED TVs) have an HDMI input slot at their back. Just insert an HDMI cable at both ends and your audio and video problems are solved as the HDMI cable can carry both audio and video. Also, Raspberry Pi can produce full-resolution HD pictures at 1920×1080 on the latest HDTV set.
However, for connecting it with a DVI monitor, just use one HDMI-to-DVI plug (available very cheap at electrical and computer stores).
Audio cable connections. In case you are using a TV, the same TV can be used as audio amplifier for the weak audio signal from the Raspberry board. Get another pair of audio/video cord, whose one end goes into the left and right audio input socket at the TV end and the other ends meet the Raspberry Pi board with a stereo pin jack. So you are all set with the cable connections.
Keyboard and mouse. The computer market is replete with USB devices, so finding a USB keyboard and USB mouse is just a child's play. Connect them to the two USB ports of Raspberry Pi. No order is required, just use any USB port for any device. For connecting additional USB devices, you will need a USB-powered hub. This kind of hub has a separate power supply of its own.
Power supply. The Raspberry requires 5 volts and 1 ampere but it works fine at 5 volts, 0.7 ampere. You can even run it well on four dry pencil cells (4×1.5 = 6 volts). But more than 6 volts may damage the Raspberry Pi beyond repair.
The supply goes to the board through a micro USB power connector that normally comes with a smartphone charger from companies like Samsung and LG. However, if you are a Nokia user, don't worry. Go to the local mobile store and get the adaptor shown in Fig. 3. That's in fact good, as the chances of damaging the onboard power socket are minimised. Besides, you can power the Raspberry Pi from most of the mobile chargers as majority are 5V, but do check the voltage rating before connecting them. Take caution, never try to power a Raspberry Pi board from another USB port of a computer as this will result in malfunction of the board.