Prototyping a smart device on the road to production is complex, time consuming, and can seem overwhelming to anyone who has limited experience in configuring electronics. But we all have to start somewhere. So here’s what you need to know about how to perform Raspberry Pi prototyping in 2023, and the tools you can use to help along the way.

Why use the Raspberry Pi?

I’ve heard experts say that the Raspberry Pi isn’t suitable for prototyping. I think part of the reasoning here is that a Raspberry Pi is typically used by hobbyists for learning more about computing and hardware, and it’s rarely used in production. Admittedly, using a Raspberry Pi in IoT is often overkill. You normally don’t need that much processing power, and the Raspberry Pi uses too much power to be practical in many IoT applications. Not to mention, it costs considerably more than the average microcontroller you might use for IoT and as a result is probably too costly for a marketable smart device.

I still stand by the Raspberry Pi as a viable option for IoT prototyping, though, particularly if you only have a vague idea of what type of final product you want from the process. The miniature computer is extremely versatile, and you can connect all kinds of external components and additional electronics for testing. Other boards like the Arduino will have fewer options. An Arduino might be a better choice if you already know exactly what you want, but that’s rarely the case in the earliest stages of a prototype.

Plus, the higher computing power of the Raspberry Pi has its benefits. The Arduino might work for a smart motion sensor, but the Raspberry Pi will be the preferred choice in a more processing-heavy application like a smart device hub. A hub is the place where all of your smart devices connect to each other digitally for centralized control, so it needs more computing capabilities than a typical smart device.

In addition, some Raspberry Pi models are extremely small and have relatively low energy consumption. The vast number of different options, robust documentation, and strong community available through the Raspberry Pi make it easy to use and a great tool. So you can use it to develop a prototype or even a minimum viable product, i.e., an early product iteration that might change based on customer feedback.

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Before you start prototyping

So what will a Raspberry Pi prototype look like? It will have four main components or aspects that you’ll need to optimize: the user interface, the hardware, the internal software, and the connectivity.

A user interface for your device might be a touch screen that you place directly on the device, and there are numerous touch screens that are compatible with Raspberry Pi devices. Or, it might be an app on a smartphone that you can use to interact with the Raspberry Pi over the internet or through Bluetooth or another communication protocol.

Once you’re chosen an interface, your next choice will be the hardware. A Raspberry Pi is just the heart of the prototype; you’ll also need other components that you can switch out and test for things like energy efficiency and functionality. Some simple examples would be a motion sensor or a light that blinks whenever the motion sensor gets set off.

Next is the internal software, also called the embedded software. “Embedded” here just means that this software is on the device you’re prototyping as opposed to being a smartphone app or web app that you use to interact with the device. I’ll give some examples of software you might use at the prototyping stage in a later section.

Finally, you have connectivity, which relates to how you will control the device externally. The connectivity options are numerous in IoT. Examples of connectivity methods would be a USB cord, Bluetooth, and CoAP. Also, Nabto provides peer-to-peer (P2P) connectivity for low latency and low-power applications.

When you get ready to start prototyping, you should have at least a general idea of what you want to get out of your device. First ask yourself, who will your consumer be? Are you looking for a user interface that’s suitable for workers in a manufacturing plant? Are you prototyping a smart home device that needs to be optimized for a general user audience? Or is your device high-level enough to focus on a developer audience?

Next you need to get into the nitty-gritty of clarifying the goals and functionality of the device. How will it be used? Will it need to be suitable for an outdoor environment or for high-temperature areas? These questions will tell you what types of features you should look for in your hardware and software. For example, if you’re building a smart security camera, you’ll want a video capture software like MotionEyeOS. You’ll also want to consider the types of peripherals – lights, buttons, sensors, etc. – that your device will require.

Understanding your goals and the functionality you’re looking for will also tell you something about the connectivity options you should consider. Different connectivity protocols require more energy or less and provide higher or lower levels of signal speed.

If your prototype is for an industrial IoT device, for example, you’ll likely want higher response speed even if that means more energy consumption. This is because in manufacturing IoT may have safety applications like quickly shutting off a machine when the temperature rises to dangerous levels or when someone comes too close. In a smart HVAC system, you’ll probably be focused on saving energy, so a miniscule difference in speed won’t be as important as low power consumption.

Skills you need for prototyping

Once you’ve answered all those questions, the next factor that will strongly influence how you’ll handle and design a prototype will be what skills you currently have and the resources you have access to. If you’re going to prototype an IoT device, you likely have some experience with electronics and coding. But if you’re fairly new to the space, there are always new skills you can learn to make the process easier.

For example, there are prototyping kits that don’t require any soldering, but if you want to go for the most versatile and customizable options, you should know how to solder. Soldering lets you connect components more securely, making the final product less fragile.

There are certain coding languages that are commonly used in the prototyping process. If you’re prototyping with Arduino, you’d need to learn C#. But for Raspberry Pi, you can use Python, which is a more common language that’s relatively easy to learn. You should also know the basics of console commands. The Raspberry Pi OS is Linux-based, so if you have experience configuring a Linux computer, you’ll be able to transfer those skills to Raspberry Pi prototyping with relative ease.

Raspberry Pi prototyping hardware

So let’s say you have your documentation, online resources, and skills in line and you’re ready to sit down and start putting together a new IoT device from scratch. Now you need some hardware. Again, the exact hardware you use will vary, but here are the different components that will make up the central portion of your project.

    1. Different Raspberry Pi models

Raspberry Pis come in a variety of different sizes. The physical size of an electronic component is called its form factor. For IoT, you’ll typically want the smallest form factor possible. That said, you’ll need to balance a small form factor with a high number of general purpose input/output pins (GPIOs).

These pins are what you use to connect your external devices, like a blinking light or a sensor. As their name implies, GPIOs are distinguished from pins that are meant for a specific purpose, like streaming video. The more pins you have, the more versatile your board will be for prototyping. You can also add additional pins and connectivity options with the help of an expansion plate that will attach to your main board.

A Raspberry Pi 4 or Zero model both have 40-pin layouts. For the full layout of the pins, see this resource. Earlier and smaller versions of the Raspberry Pi have 26 pins. These typically have much more limited functionality.

In the early stages of prototyping, you will likely want as many options as possible, so you’ll want a 40-pin layout. There’s also the much more compact Raspberry Pi Compute Module 4 (CM4) that’s smaller and has fewer ports. If you choose the CM4, you’ll need to invest in more connectors and pre-configured circuit boards to stack on, or attach to it if you want to add more functionality.

    2. Breadboards

A breadboard is an essential component for prototyping. It looks just like a piece of plastic with holes in it, but in reality, you’ll be using a breadboard to connect all of your components and to design the layout of your board. I recommend a solder-free breadboard for the easiest experience.

There are also breadboards of different sizes. You might want to start with a larger breadboard unless your device is intended to be extremely limited in its functionality, in which case you probably would have been better off with an Arduino than a Raspberry Pi anyway. Some breadboards come pre-mounted to a stand of some kind to make them more stable during the prototyping process. It’s up to you whether or not that’s important.

    3. Power supply

Many prototyping kits will come with a power supply, but if you just bought a Raspberry Pi model and want to build a kit yourself, you’ll need a separate option. Raspberry Pis don’t have a place for batteries onboard, so you’ll need an external power source. You’ll need to do some research to discover what works best for your particular model.

    4. Switches and other peripherals

Again, a prototyping kit will come with some switches and peripherals already, but you can add switches to change sensor sensitivity, for example, among other things. As for peripherals, most IoT prototypes start with a simple blinking light. It’s the hardware equivalent of the “hello world” program that software developers typically start with. You might want a display of some kind to show temperature data, etc.

    5. Wires and cables

Choosing wires for the prototyping process is comparably simple. Generic 22-gauge solid wire will do, or you can find pre-made breadboard wires by searching online. I would suggest having multiple colors available so you can differentiate different peripherals, voltage requirements, and power supplies as you go along. You may also want USB or Micro USB cables and HDMI cables.

Useful software for IoT Prototyping

Hopefully by now you have all of the hardware you need and you’re ready to look at software options. I already mentioned MotionEyeOS for video recording. You’ll also want access to the default operating system for a Raspberry Pi: Raspberry Pi OS (originally called Raspbian), which is based on Linux.

You can categorize the types of software you might use like this:

  • Apps and software for the planning process, including simulating different hardware designs
  • Web and mobile apps for interacting with your device
  • Embedded software for specific functionality, like temperature monitoring or video recording
  • Connectivity software for connecting multiple devices or creating the bridge between a smartphone and your Raspberry Pi prototype

On apps for the planning process, there’s DipTrace, a software that’s also open source and provides a lot of tools and documentation for newcomers to the IoT hardware space.

As far as web and mobile apps, rather than building a completely new app to interact with your device, you can streamline prototyping by using a pre-built app, which will allow you to focus on hardware configuration and testing out connectivity options. For this purpose, Nabto provides an RTSP video streaming app that’s ideal for any type of video streaming Raspberry Pi prototyping. Nabto also provides a thermostat demo app. Both are open source and easy to customize.

When it comes to embedded software, MotionEyeOS was the example I gave earlier for capturing video, but you can actually use most software that you could use on Linux as well. You can add computer vision capabilities through software like OpenCV or stream weather and environmental data through Adafruit IO. The possibilities are seemingly endless.

For connectivity and device management, the Nabto Edge platform is a prime example. Nabto allows you to create a direct P2P connection between your Raspberry Pi prototype and a controlling device like a smartphone or a computer. Since the connection bypasses the cloud, it’s secure and low-latency.

Final thoughts

There’s always more to learn about Raspberry Pi prototyping, and there are always new projects you can do and new resources to utilize. Discover how to make the most out of your prototypes and IoT products with low-latency P2P connectivity by contacting us today.

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