Install Raspbian get connected and basic networking

In this activity, we will show you how you can get started with your Raspberry Pi. Some of you may have done this before and there are easier ways to do this. The most simple way to get started with a Raspberry Pi is to buy a pre-installed sd card running NOOBS. You can then plug in a monitor, keyboard and mouse.

The aim of this unit is to teach you some fundamentals of IoT device, so it is important that you can use a serial connection on an IoT device which may not have an Internet connection. Secondly, we have devised an IoT and a unit with no additional assumptions above a laptop and a phone. So we are assuming that you don't have a spare keyboard, monitor and mouse available.

Downloading and Flashing Raspbian on an SD Card

Start by downloading the Raspbian Lite image: https://www.raspberrypi.org/downloads/raspbian/

The reason that we will use the Raspbian lite image is that it does not use a graphical user interface. We will do our best to keep students on the command line as this is how most IoT devices will run, in "headless mode".

While the image is downloading, please find, Download and install Balener Etcher from: https://www.balena.io/. We will use Balener Etcher to safely install the image to your sd card. It works on Windows, OSX and Linux and does a pretty good job of preventing you from writing the Raspbian image to any of your computer's drives.

Insert your SD Card, into your USB-SDcard reader. Then insert the USB-SDcard reader into your computer.

Open the BalenerEtcher software on your computer. Pick "Flash from file" and then find your downloaded Raspbian image name it usually start with a date like "2020-06-13-raspbian...."

Finally, you must select your drive, note the capacity of your purchased MicroSD card and ensure that you are flashing a device with the same capacity. Note that the number on the box will slightly overestimate the actual capacity. I purchased a 16GB MicroSD card and Balener Etcher reports it as a 15.5GB MicroSD card. After this, click flash and enter your password if required.

Enabling the TTL/Serial Lines

At this point, we have our SD card flash. If we wanted we could plug in a keyboard and monitor, but we are going to assume you don't have these and enable the serial lines. Serial connections have been used for over 20 years to connect to Internet Routers, Switches and all types of hardware. It is very important that you get familiar with how this works.

By default, the TTL/Serial lines are off, we are going to switch them on. Eject and then replug your USB-SDcard reader back into your computer. Find the partition called boot. Within here, find the file called config.txt Edit this file and at the bottom, on the last line, add

enable_uart=1

Save the file and exit.

USB to TTL/Serial

You should now remove the MicroSD card and put it in your raspberry pi.

Plug in the USB to TTL cable into your laptop. Wire the other end as shown in the diagram.

Do not connect the red wire as this will attempt to power, but may undersupply your raspberry pi. We will provide a regular power source to power your raspberry pi. See the diagrams to your right for the correct physical wiring.

In the next step, we will read and write the serial text from your USB cable. How you do this will depend on your operating system.

Windows

Install putty from:

http://www.putty.org/

You will also need the drivers Prolific Chipset drivers from here: http://www.prolific.com.tw/US/ShowProduct.aspx?p_id=225&pcid=41

Start Putty then select a connection type "Serial" from the radio buttons. Set the speed to 115200 and the serial line to COM7.

Finally click 'Open' to connect. Remember to press ENTER to start communications.

Mac

On a Mac open a Terminal window and issue the command:

ls /dev/cu.*

Linux

sudo apt-get install screen

Then run the following command:

sudo screen /dev/ttyUSB0 115200