Setting Up Raspberry Pi 3 Model B+

Please refer back to Figure 3-1 in Chapter 3 for a schematic diagram on the components that you need to set up for the case studies. There are two software components, the Python IDE and the Arduino IDE, which you will set up once you have the hardware components fully set up. So let’s get started with the hardware.

The first step to setting up your Raspberry Pi 3 Model B+ hardware is to decide on the operating system that you will use to run your applications. There are two popular operating systems available: Raspbian and Noobs. Noobs is used by people who are new to Raspberry Pi. You will be using the Linux version Raspbian, which is available from www.raspberrypi.org/downloads/. It can be seen in Figure 5-1, which shows the available operating system images for download from the official Raspberry Pi website.

Note that at this stage you have not booted up your Raspberry Pi 3 B+ as there is no operating system installed on its microSD card yet. A microSD card and microSD card reader or adapter come with the Raspberry Pi 3 B+ kit. If you do not have a microSD card, you can get one from the options on my website at www.pmauthor.com/raspbian/. For the installation of Raspbian, the base suggested microSD card size is 8GB. For Raspbian Lite image installations, Raspberrypi.org suggests at least 4GB. Do keep in mind that just the Raspberry Pi 3A+, 3B+, and Compute Module 3+ can boot from an SD card bigger than 256GB. This is because there was a bug in the SoC utilized on past models of Pi. Also remember to note the microSD card class to which your microSD card belongs because that decides the supported writing speed for it; a class 4 card will most likely write at 4MB/s, while a class 10 ought to accomplish 10 MB/s. Do note this does not mean a class 10 card will beat a class 4 card for general read/write performance, in light of the fact that frequently this write speed is accomplished at the expense of read speed and a substantial increase seek times to the microSD card operations. The microSD card that comes with your Raspberry Pi 3 B+ kit should be latest and should most probably be class 10, as is common now; however, if you get a lower class like 4, you can order a faster card of class 10 at www.pmauthor.com/raspbian/.

Of course your laptop must have a slot for reading and writing to microSD cards either directly or through an adapter. This is shown in Figure 5-2. Also, you will need a computer or a laptop that is running either Windows or MacOS in order to download this image and then format the SD card and install this image on to it. I will show you how to do this on a Windows system in this chapter.

Do not insert the microSD card adapter into the Raspberry Pi 3 B+ board yet because it is empty and not formatted with any operating system image written on top of it yet. You need to first download the Raspbian image by clicking the download section of the website. Once you do so, you will get the option to download the latest image of Raspbian for your use. As of the writing of this book, the there are three options for download, as shown in Figure 5-3.

The first option is the Raspbian Buster, which is the name of the Raspbian flavor available for the desktop and recommended software. The second option is only the desktop and the third is the Lite version, which does not have all the features needed for you to do extensive programming for your IoT applications. So you will use the first option, which provides all the components of the software necessary to get going. You can click the Torrent or zip file depending on the software that you use to unzip it. I used the zip file version. The zip file for the Buster flavor of Raspbian is approximately 2.3GB so it takes time to download depending on your internet connection speed.

Once you have this downloaded, you need to insert your microSD card reader into the computer/laptop from which you are installing the operating system onto the SD card slot. Since you are using Windows, you will need a disk imaging utility. The free utility that I use is Win32 Disk Imager. If you do not have it, you can download it from this page: www.pmauthor.com/raspbian/. Once you have installed the Win32 Disk Imager utility after downloading it from the website, you can open it by double-clicking its icon. It should look like the one in Figure 5-4.

Click the browse icon shown in the figure and locate your unzipped image file where you downloaded it. After selecting the location of the image file, click the Device drop-down box on the right-hand side and select your microSD Card drive letter from it. The Write button on the dialog box will get enabled, so click it to write the image. The progress bar will show you when it is done; this should not take more than a few minutes. Once it is done, click the Exit button to eject the microSD card. You now have an image of the latest Raspbian OS written on your microSD card and ready to boot. Before you can boot, however, you need to set up the SBC physical wires on the board and then attach the microSD card to the Raspberry Pi 3 B+ board.

The second step to setting up the Raspberry Pi 3 Model B+ is to get its board wired as shown in Chapter 2 with photos of the GPIO pins and the various components of the SBC. You need to plug in the bare minimum to get started. First, you need an LED/LCD TV or a display. There are many available, but the ones I prefer and use on my projects are listed at www.pmauthor.com/raspbian/. If you have a spare TV, you can use the HDMI-to-HDMI cable to connect it from your TV to the HDMI port on the SBC. See Figures 5-5 and 5-6.

If you have a small 5-inch or 7-inch display, then you will have a different cable and you may not have an HDMI slot on the compact LCD/LED panel.

The connected Raspberry Pi will look like the one in Figure 5-7. Make sure you get the connections right and do not to leave them loose in the port on both sides (the TV display and the Raspberry Pi 3 b+) or your display will not show up. This is a common beginner problem; after you power on your Raspberry Pi, you don’t see the display coming up and you wonder what happened. It’s an easy mistake to fix because the HDMI ports on the Raspberry Pi are quite large so you can see if the wire is secured properly on to the board. Also, make sure you do not power on the Raspberry Pi 3 B+ when you are fixing the HDMI cable onto it; this is important both as a safety precaution and as an operational requirement. Sometimes, when you have a powered-on Raspberry Pi and you fix the HDMI cable into its HDMI port, the display won’t show up. In this case, restart the Raspberry Pi 3 B+ as there is no reboot button on this SBS.

There are two things I recommend doing before you finally boot up your Raspberry Pi. The first is to insert a USB mouse dongle into one of the four USB ports on the Raspberry Pi 3 B+ board. The second is to add another USB dongle for a wireless keyboard. These are essentials for you to control your SBC. You can see them connected to the SBC in Figure 5-7. Don’t worry if you do not have a wireless version of a mouse or a keyboard; the wired versions of the USB mouse and keyboards work pretty well. It’s just that the wired devices prove to be a bit too heavy for the SBC, which is very light and can move around if the wire of the mouse or keyboard shakes.

Next, to get your Raspberry Pi to boot up, you need to plug it into a power source. The wonderful thing about this small SBC is that it uses microUSB as its power source. This means that you can power it via a power bank as well by attaching a microUSB power cable to it. Why do you need a power bank? It provides a power backup so that it does not shut down when the power goes off. This is important if you live in a region of the world where power cuts are frequent. If your region has stable power, then you do not need to connect to a power bank and you can connect it to the power source through a power adapter charger. You can see my connection to a power bank in Figure 5-8.

What you see in the image is a Portronics 10000mAH power bank. It provides power for commercial applications for a few hours. In one of our factory energy audit applications, we had to create a power bank backup with one power bank connected to another one in serial, the first one feeding into the another one, so that even if the power went off for a few hours, the Raspberry Pi energy audit applications running on it would not be affected. Sometimes you need to think out of the box to build commercial grade applications that can take power cuts in its stride.

Now to bring your Raspberry Pi 3 B+ to life you just need to insert the microUSB side of the power cable into the power slot of the SBC, as shown in Figure 5-9. Please remember that if you have connected to a power source or a power bank and you are inserting the wire in the SBC, it will boot up in your hand. To prevent this, make sure the other end does not have power when you connect the microUSB to it.

Now you are ready to boot up your device, so go ahead and switch on the power to your power adapter, which is connect to microUSB power cable. You will see a green LED blink near the HDMI port slot and the connected LED/LCD monitor should show the booting up image you saw in Chapter 3. Now you just have the basic Raspberry Pi with the latest version of Raspbian installed onto it. Next you need the software to be installed in order to work with the IoT sensors and devices.

Test your Python 3 installation on the Raspbian by typing the command given in Figure 5-10.

Now that you have the required Python version installed and tested, you need an integrated development environment (IDE) to program on Raspbian. I recommend you use the Thonny IDE because it lets you compile programs and run them in a single place inside an editor. I have discussed the need and features in Chapter 3 so let’s get straight to the steps you need to install it on your Raspbian.

The Raspbian package for the Thonny IDE is downloaded from the archives of the raspberry.org official website and then processed and set up for use. If the installation is successful, you should see your IDE installed under the Programming menu in the Start bar, as shown in Figure 5-11.

Now that you have seen the Python libraries that you need for the case studies, go ahead and install them. I created a script that does so on the Raspbian command line; see Figure 5-10. Please remember that the code is to install on Python 2.7; your need to change the script to add a 3 to pip and make it pip3 if you want to install all the libraries on Python 3.

So no errors were found in this file and the python nltk library was installed successfully. You may want to check all the other log files that were installed for you one by one, like scipy.log, statsmodels.log, etc. Now you have successfully installed all the required Python libraries.

Installing the Arduino IDE

Since you know your processor bit width, you can move to the actual installation of the Arduino IDE, which can be done in two ways. One way is to go to www.arduino.cc and click Software ➤ Downloads, as shown in Figure 5-12.

Now scroll down to the Arduino IDE download section shown in Figure 5-13 and choose the operating system with the corresponding bit (32 or 64) for download.

As you can see, there are various options in the blue bar on the right-hand side of the page. Linux has four options: Linux 32 bits, Linux 64 bit, Linux ARM 32 bits, and Linux ARM 64 bits. The uname and lshw commands showed that I am running Linux on an ARM v7 processor with a width bit of 32 bits, so I select Linux ARM 32 bits for download in my case. If you have a 64-bit processor, you need to download the Linux ARM 64-bit IDE. Click the Just Download button on the next page if you do not want to contribute a small donation towards Arduino development.

After the download ends, follow the steps given in Figure 5-14 by clicking Show in Folder option in your browser.

After this, the Raspbian GUI File Explorer will open the Downloads folder where the Arduino compressed file has been downloaded, as shown in Figure 5-15.

You need to extract the tar file from inside the ∗.xz extension file, as shown in Figure 5-16. Right-click the file to select and left-click the Extract Here menu option.

When you click the Extract Here option, you will see a dialog box that will show you the progress of your file extraction process. See Figure 5-17.

Once you have this extracted, you will be able to see a new file created in the Downloads folder with the same name as the ∗.xz file but now with a ∗.tar extension. Right-click this file again and select the Extract Here option from the dropdown menu once again, as shown in Figure 5-18.

After the extraction process is complete, you will now see a new folder created, as shown in Figure 5-19.

You can go into the folder by double-clicking it, as shown in Figure 5-20. You will see a file named install.sh . Double-click this file and the Arduino IDE will be installed on your system.

Although the command line method of installing the Arduino IDE is much simpler and has lot less steps, some people like the GUI more than the command line, so I have shown both the methods and leave it up to you on how you want to install it. Now you are at the data storage step in your setup, that of installing a SQLite3 database on Raspbian.

Installing SQLite3 Database

SQLite3 is a free database that you are going to use easily to create and use a database in your applications for storage. Although SQLite3 is not a full-featured database, it supports a large set of the SQL standard and is great for application development that need a simple database engine to plug into applications. SQLite3 is very popular with smartphone developers. The environment of the Raspberry Pi is also a mobile environment where we take it on the field, in factories, in agricultural fields, or near mobile towers to gather data through IoT sensors and store it in this compact, robust database. Please remember that you can’t use this database for applications that require high security features like built-in user management. So use it wherever there is no such security requirement. You can configure PostgreSQL or any other Linux database like MySQL on Raspbian but that is beyond the scope of this book since we are developing only PoC-grade code.

You can also install SQLite3 in the manner I showed you for the GUI installation for the Arduino IDE from the official website of the SQLite organization at www.sqlite.org/download.html.

Now you’ve come to the last step of installing the Modbus interface device, the single phase meter, onto the Arduino.

The additional devices that you will be using to set up the energy meter are shown in Figures 5-21 through 5-23:

1. 1.

   Schneider Electric Conzerv EM6400 Series Power Meter

    

1. 2.

   5V RS485 to TTL Signal Mutual Conversion Module for Arduino Overvoltage Protection with Signal Indicator

    

Let’s now connect the wires between the Arduino Mega 256 and the 5V RS485 Modbus Conversion Module. I have shown the wires attached to the Modbus Conversion Module in the Arduino Mega 2560.

In order to connect the Modbus Conversion Module to Arduino, you need to first understand the layout of the Arduino Mega 2560 PCB, which is shown in Figure 5-24. Notice in the diagram that the upper pins pertain to communication and the GPIO pins. The right side of the board has the data pins and the bottom part of the board has the power and analog pins. This board is very different from the Arduino Uno board because it is used for controlling multiple slaves and is used in industrial applications. This is why there are so many data pins in the PCB layout.

Now connect the Modbus Conversion Module to the Arduino Mega board. You have to connect three pins to the power area of the board, which is near the power controller on the bottom left-hand side of the layout diagram in Figure 5-24. The left-most dark blue pin gets connected to the pin that has 5V written under it. The next green wire is connected to the immediate next pin marked as GND. Ignore the yellow wire on the left of Figure 5-24; you don’t need it for your setup. You can see this in Figure 5-24—the three pins connected to the power section of the Arduino Mega board. Please remember these are male jumper wires that you need because the Arduino Mega board only has holes and not pins like the Raspberry Pi GPIO setup.

The wires on the other end have to be female jumper wires because the Modbus Conversion Module has pins to put the wires into. So you should have two male-to-female jumper wires for this connection. Connect the other end of these two wires to the Modbus Conversion Module pins marked as VCC and GND (VCC is the 5V power wire and GND is the grounding of the circuit). You can refer to Figure 5-25.

The 5V dark blue wire connected on Arduino connects to the VCC pin marked on the Modbus Conversion Module. The GND green wire pin on the Arduino board connects to GND on the Modbus Conversion Module PCB.

Now one part of your Modbus Conversion Module is connected to the Arduino board. You need to connect the other end to the GPIO pins section of the Arduino board or the communication side for a total of four pins. See Figure 5-26. On the Arduino board

As you can see, there are two pins on the left-hand side of the board named PWM connected to pins numbered 3 and 2, which are adjacent to each other. The next two pins are connected to the communications pins 18 and 19, which are marked as TX1 and RX1, respectively, on the Arduino Mega board. Once you have this in place, you need to connect the other end of the four pins in the following manner. Pin 1 connected on the Arduino board to pin number 3 of PWM needs to connect to the pin marked DE on the Modbus Conversion Module pin. Pin 2 connected on the Arduino board to pin number 2 of PWM needs to connect to the pin marked RE in the middle of the Modbus Conversion Module. Similarly, pin 3 connected on the Arduino board to pin number 18 in Figure 5-27 needs to connect to the pin marked DI on the Modbus Conversion Module. The fourth pin connected to pin number 19 on the Arduino board should be connected to the pin marked RO on the Modbus Conversion Module. This completes the wiring process for the Modbus Conversion Module to the Arduino Mega board. You can check your connections against Figure 5-27.

Now you are ready for the next step: to connect your Arduino module to the Raspberry Pi board. For this, you need to connect a serial USB wire from the serial USB port of the Raspberry Pi 3 B+ board to the Arduino Mega 2560 board. The wire is shown in Figure 5-28 for clarity.

Now you are finally ready to power on your complete system. The Arduino does not need a separate power cable, although it has a slot for it on the board. The serial cable powers on the Arduino Board because it is a slave of the Raspberry Pi 3 B+ board. When you power on the Raspberry Pi 3 B+, you should see LED lights on the Modbus Conversion Module and the Arduino Mega 2560 board. This signals preliminarily that your connections are successful. This can be seen in Figure 5-29.

If the board or the module does not light up, you should check your connections again, especially the ones supplying power to the module or the Arduino board. Now go ahead and run the Arduino Hello world program from Chapter 3 to confirm the serial communication between the Arduino Mega slave and Raspberry Pi 3 B+ master.

Summary

This chapter was about preparing your setup for the case studies implementation. You are now fully configured by setting up the Raspbian OS on the Raspberry Pi 3 Model B+ and downloading it from the www.raspberrypi.org download options. You used the microSD card and microSD card adapter to get the OS. Then you used the Win32 Disk Manager to unpack and extract the package. After this, you used the HDMI-to-HDMI cable in order to connect the Raspberry Pi to a TV monitor. You used USB dongles to connect a keyboard and mouse to the SBC. After this, you connected the Raspberry Pi 3 B+ power cord to a power bank so that its power connection would be failproof in case of a power outage.

You then installed Python and tested it on Raspbian. Next you installed and verified the Thonny Python IDE. You then ran a Raspbian command line script to install the required Python packages

You ran a script to test the installation of the Python advanced packages and to check for errors. You installed the tkinter package on Python for a GUI implementation and then successfully executed tkinter on the Python 3.x interpreter. After this, you ran the iotpypackages.run Raspbian script to install the IoT Python packages on Raspbian.

After this, you finished installing the Arduino IDE by running the install.sh file. You installed a SQLite3 database for storing data from IoT sensors. After this, you installed the Modbus interface device, the single phase meter, onto the Arduino. You configured and connected the three devices, the Schneider Electric Conzerv EM6400 Series Power Meter, the 5V RS485 to TTL Signal Mutual Conversion Module for Arduino Overvoltage Protection with Signal Indicator, and the 5V Modbus Converter Module. After this, you made the Modbus converter wire connections to the Arduino Mega board and connections to the PWM and communications side of the Arduino Mega board. You wired the Modbus Conversion Module communication and PWM pins through the USB serial cable to connect the Arduino Mega 2560 with Raspberry Pi 3 B+. After this, you performed the final power on for your complete system.

With this you come to the end of setting up your system, including the hardware and software. You can now proceed with the case studies.