IoT Characterization of This Project

Ratings are from 1 to 10, 1 being the least suitable for IoT and 10 being the most suitable for IoT applications. This gives us a CPLPFC rating of 5.7. Great for learning, not so good for deployment for most applications.

No doubt about it, the Raspberry Pi is a very flexible and powerful IoT platform. However, the power consumption, cost, and physical size of the device make it more suitable for prototyping or for stand-alone, highly functional IoT units.

How Does This Device Hook Up to the IoT?

With SkyWeather2, hook up to the Internet using the WiFi connector. We can use the SDR (software-defined radio) to hook up to 422MHz wireless local IoT weather sensors, and we can also use the Pi SkyWeather2 Hat to connect to other wired devices. In this chapter, we will be using the WiFi interface to talk to the outside world.

Data Gathering

The SkyWeather2 uses 13 different sensors to detect weather connections. Because I am using a Raspberry Pi and have good storage mechanisms and disk space, I use a MySQL database to store all the weather data for future analysis and download. We also use the dash_app to build graphs locally and use an iOS app called Blynk to display the information across the Internet. WeatherSTEM is used to show our local weather on the cloud.

What Are Grove Connectors

Grove is a modular, standardized connector prototyping system. Grove takes a building block approach to assembling electronics. Compared to the jumper or solder-based system, it is easier to connect, experiment, and build and simplifies the learning system, but not to the point where it becomes dumbed down. Some of the other prototype systems out there take the level down to building blocks. Good stuff to be learned that way, but the Grove system allows you to build real systems. It just makes it easier to hook things up.

The Grove system consists of a base unit and various modules with standardized Grove connectors.

We use Grove connectors and cable in building SkyWeather2. This means no soldering is needed to build this project.

See a full tutorial on Grove cables and connectors on SwitchDoc Labs:

www.switchdoc.com/2021/01/tutorial-intro-to-grove-connectors-for-arduinoraspberry-pi-projects/

And a great example of projects using Grove connectors:

www.switchdoc.com/2018/12/tutorial-using-an-analog-to-digital-converter-with-your-raspberry-pi-2/

The Project – SkyWeather2

This chapter will show you how to build a SkyWeather2 Raspberry Pi Weather Station. This project grew out of a number of other projects, including the massive Project Curacao [www.switchdoc.com/project-curacao-introduction-part-1/], a solar-powered environmental monitoring system deployed on the Caribbean tropical island of Curacao. Project Curacao was written up in an extensive set of articles in The MagPi magazine (starting in Issue 18 and continuing through Issue 22).

The included SkyCamera Pi Camera allows you to take pictures of your local conditions and upload them to WeatherSTEM. WeatherSTEM builds time-lapse movies every night and uses your latest picture as backdrop to your weather station data as shown in Figure 3-3. Figure 3-4shows you the overall architecture of the SkyWeather2 system.

The Architecture of SkyWeather2

This looks really complicated! It is not. There is a step-by-step assembly and testing manual that makes it a “snap” to put together and test.

The major parts of the kit are as follows:

• WeatherRack2 433MHz wireless sensors (see Figure 3-5)

• Software-defined radio

• SkyWeather2 Hat (see Figure 3-6)

• SkyCamera (see Figure 3-7)

• Raspberry Pi (see Figure 3-7)

What Do You Need to Build This Project?

SwitchDoc Labs has organized all the parts for building SkyWeather into a kit and few optional items. Later on in this chapter, I will talk about the 3D printed case for SkyWeather (Figures 3-9 and 3-10) and the weatherization parts needed.

Connecting and Testing the Hardware

SwitchDoc Labs has published excellent step-by-step assembly and testing manuals for SkyWeather 2. The latest versions of these are all available on the SkyWeather2 Product page: https://shop.switchdoc.com/products/skyweather2-raspberry-pi-based-weather-station-kit-for-the-cloud

If you will be putting your SkyWeather2 station outside (highly recommended to get a good SkyCamera view), then look at the 3D printed cases and the Weatherization Manual later in this chapter. The assembly process is very straightforward (see Figures 3-6 and 3-7).

Weatherization and the 3D Printed Box for SkyWeather2

Because of the unique architecture of SkyWeather2, the main Raspberry Pi system does not require the entire system to be outside. However, many people prefer to mount the unit outside to capture a better sky picture, and if they are using the optional laser AQI (air quality sensor) to capture the outside air quality in their neighborhood.

Many people now have access to 3D printers so it makes sense to build custom 3D printed boxes for projects like SkyWeather2 as shown in Figure 3-10. If you don’t have access to one, you can find the complete 3D printed case on shop.switchdoc.com – search for SkyWeather2 3D Prints.

Figure 3-9 shows all of the 3D printed parts for the SkyWeather2 kit. It takes about 25 hours to print out one full part set on our QIDI X-Max printers in ABS plastic.

All the 3D Print STL files and the Fusion360 Design files are on https://github.com/switchdoclabs/SDL_STL_SkyWeather2 for those who want to print or modify the design.

The required assembly parts list and a step-by-step assembly and weatherization manual are located on the SkyWeather2 Product page on shop.switchdoc.com.

• SkyWeather2 WeatherProofing and Test Manual – www.switchdoc.com/wp-content/uploads/2020/12/SkyWeather2WeatherProofingAndTestManual1.1.pdf

The Software

A big part of the SkyWeather2 project is the software. All of the Python software for this project is up on github at the switchdoclabs section [https://github.com/switchdoclabs/WeatherPi]. I also included all of the various libraries for the I2C devices we are using.

The Software-Defined Radio

A key part of the SkyWeather2 project is the software-defined radio. A software-defined radio (SDR) is a radio communication system where components that have been traditionally implemented in hardware (e.g., mixers, filters, amplifiers, modulators/demodulators, detectors, etc.) are instead implemented by means of software on a personal computer or embedded system (still with significant hardware support).

The SDR scans, reads, demodulates, and decodes the incoming 433MHz signals from the WeatherRack2 and other optional sensors. Figure 3-12 shows the block diagram of an SDR system.

The SDR we are using with SkyWeather2 is based on the powerful RTL2832U and R820T tuner; it can tune into signals from 24MHz to 1850MHz. SwitchDoc Labs has written drivers for the WeatherSense weather sensors and supplies the drivers to the community open source.

The SkyWeather2 Configuration Software

Before you run SkyWeather2, you will use a Python configuration program showing a GUI (graphical user interface) for setting up your unit just the way you want. Figure 3-13 shows a page from the SkyWeatherConfiguration.py software.

The SkyWeather2 Configuration Manual contains detailed information about the SkyWeather2 Configuration software [www.switchdoc.com/wp-content/uploads/2020/12/SkyWeather2ConfigurationAndOperationsManual1.1.pdf].

The Dash App Local Display

The SkyWeather2 software also includes a dash_app that runs a browser-based set of displays and graphs that can be accessed on your home network. What is a dash_app? Dash is a powerful framework for building complex interactive data visualizations using pure Python. As with all of our SkyWeather2 software, the Dash App source code is supplied in github/switchdoclabs/SDL_Pi_SkyWeather2. Figure 3-14 shows one of the Dash App screens connected to SkyWeather2. Note the very, very cool wind rose in the upper right.

There are other Dash App pages showing a variety of historical weather information as shown in Figure 3-15. Note especially the optional local Air Quality Index graph.

SkyWeather2 and Blynk

Blynk is a digital dashboard for your iOS or Android device that allows you to easily build graphical interfaces by dragging and dropping widgets. Blynk runs on iOS and Android apps to control Arduino, Raspberry Pi, and the like over the Internet.

It’s a digital dashboard where you can build a graphical interface for your project by simply dragging and dropping widgets.

Blynk gives you current status of your SkyWeather station including solar power status (coming in 2021), thermal status, and current conditions. Updated to your phone every 30 seconds (see the updateBlynk status task in the scheduler task descriptions in Table 3-2). Figure 3-16 shows the front screen of the SkyWeather2 Blynk application on an iPhone.

Supplying Your Data to the World – WeatherSTEM

There are a number of websites and companies that would love you to send them your weather data. Two of these are WeatherSTEM and WeatherUnderGround. For the purposes of this project, we will send the data to WeatherSTEM.

That's right. Your SkyWeather2 station and sky pictures will be visible to everyone on the Internet, and you will be sharing your local weather with locations all over the globe!

WeatherSTEM is an innovative cloud-based weather education platform for people of all ages and professions. Our innovative curriculum is designed to help you and your students understand the myriad ways weather impacts just about everything in our lives. SkyWeather2 is a great way to become part of the WeatherSTEM community.

One of the things WeatherSTEM produces is a daily time-lapse video of your SkyCamera. Take a look at this example on YouTube:

https://youtu.be/3Ogux1sY5Vo

Figure 3-17 shows a still cut from a time-lapse video from WeatherSTEM.

Tweeting Your Weather Data

Tweeting is a great way of reading short messages from people with little to say. With the SkyWeather2, you can join this epic project to be in on the fun. Of course, some people do have interesting things to say, and now you can start tweeting weather information. You may not have a lot of followers, but you can follow your IoT SkyWeather2 from anywhere!

Figure 3-18 shows an iPhone screenshot of the resulting Tweets from our test software. SwitchDoc Labs will be adding the Weather Tweeting capability in an upcoming SkyWeather2 release.

Conclusion

In Figure 3-19, you can see the complete SkyWeather2 station out in the wild and you can see the WeatherRack2 433MHz sensors mounted outside.

It is amazing what you can do with hardware such as the Raspberry Pi and off-the-shelf sensors to sense the environment. With a CPLPFC rating of 5.7, SkyWeather2 is probably not a commercially deployable system in the IoT, but it is a great base unit to experiment with and get familiar with hardware and software for the IoT.

The main power expense in SkyWeather2 is the Raspberry Pi. By replacing the Raspberry Pi with a small Arduino (and dramatically reducing the functionality – Arduinos aren’t anywhere near as powerful as the combination of the Raspberry Pi and Linux), you could improve your CPLPFC rating substantially. Want to see how to use an Arduino with the SkyWeather2 WeatherRack2? Check out this article on www.switchdoc.com:

www.switchdoc.com/2020/11/tutorial-arduino-433mhz-weatherrack2/

Next? We move on to using the Raspberry Pi to detect iBeacons and figure out where you are when you carry the RaspberryPi around with you. With BeaconAir, we will modify the lights using Philips Hue lights to light your way.