Unboxing the Raspberry Pi

It is important to know that an insufficient power supply current capability could result in an installation that is unreliable and proves hard to diagnose when problems occur. It's OK to have a power supply capable of delivering more current than needed; the system only draws the current it requires.

The most common guidance for the Pi B is a 5-Volt power supply providing between 700 mA and 1 Amp and for the Pi B+ and Model 2-B, between 600 mA and 2 Amp. The higher power requirements for the Pi B+ and Pi 2-B (four USB connections) enable connection to a wide range of USB peripherals such as USB disks, portable printers, scanners, and so on.

We used an AmazonBasics seven-port USB hub (see the following image) which has two ports that can provide over 1.2 Amp each, and five more ports that can provide up to 500 mA per port. It has a power supply rated for 5V at 4A, which cannot support maximum power on every port simultaneously (rarely required in any realistic configuration).

Our multi-Pi development environment is shown in the following image:

Before you can decide how to power your Pi, you must determine the highest level of current required to ensure that your devices can be properly supported in the configuration. We will continue to discuss power issues as they arise throughout the projects.

Our Pi is powered by a single AmazonBasics hub. The Pi and the hub are attached to a small piece of medium-density fibreboard (MDF) board using Velcro, which is an easy way to connect peripherals while designing a project. There is a WiFi adapter, keyboard, and mouse plugged into the hub. We normally connect via an Ethernet network interface, which facilitates the testing of a broader range of networking scenarios. You will notice in our configuration that a Pi-cam is connected and that we have a Microsoft webcam at the top of the right-hand side speaker.

A development desktop power/USB configuration like the one we showed in the preceding image will provide you with a stable development platform for our project designs. Of course, most final designs may require only the four USB ports on the motherboard and consume as little as 300 mA on average. The following list is the minimum configuration required to complete the projects in this book: