How can you design and develop Internet of Things applications?

That's not the first step at all! Before even choosing the hardware or software platform, you need to define the Use Case, and the Business Case. I've seen a lot of projects fail because people think about cool projects, cool gadgets, modern platforms, but have no idea about the business benefits of what they'd do with what they created. Some projects don't necessarily fail because they can't be done... but because there's no point to it. As Alberto Savoia says: "Make sure you are building the right it, before trying to build it right!"

Identify the Use Case: Start by defining the specific problem or use case you want to address with your IoT application. Consider the industry, domain, and the goals you want to achieve. Define Requirements: Determine the technical and functional requirements of your IoT solution, including the types of sensors and actuators needed, data processing requirements, connectivity options, and user interface considerations.

Beyond the initial considerations of cost, compatibility, and performance, prioritize components that align with efficient power utilization. Evaluate the power requirements of each hardware element and assess their impact on the overall energy consumption.

In our construction IoT endeavors, defining the specific need was important. Employing WakeCap's smart wearables and plug-n-play sensors transformed our data connectivity, improving safety and productivity at the job site.

Start with the User Story break the benefits/problems into smaller solutions turn these problems into system requirements define the hardware that can support the requirements finally keep in mind the system flexibility to have future upgrades and OTA updates

Embrace a modular code architecture to enhance the scalability and maintainability of your application. Instead of creating a monolithic codebase, structure your code into discrete, reusable modules that encapsulate specific functionalities.

Home Automation: IoT devices are commonly used in smart homes to automate tasks like controlling lighting, thermostats, and appliances. This automation improves energy efficiency, saves money, and enhances comfort. Security: IoT-enabled home security systems provide real-time monitoring and alerts for break-ins, fires, and other emergencies, giving homeowners peace of mind. Health and Wellness: IoT devices, such as fitness trackers and smartwatches, help individuals monitor their health and fitness levels, encouraging a healthier lifestyle. Convenience: IoT-driven voice assistants (e.g., Amazon Alexa, Google Assistant) simplify tasks by allowing users to control various devices, get information, and perform actions using voice commands.

After you have defined why you're going to build what you want, and making sure it would make sense to build it, try building a prototype first. There are several tools to help you do this. You can start with small and cheap solutions in the market, like Node-Red and Raspberry PI to build it. You can then simulate the sensors if they don't exist already. Then, after the prototype is up and running, check and see again if the Use Case and Business Case still make sense. Then you can move on and make sure that your architecture still makes sense using the prototype data being generated.

Opt for a scalable cloud architecture that aligns with the dynamic nature of IoT applications. Design your cloud infrastructure to seamlessly handle fluctuations in data volume and device connections.

Now, that you have validated your Use Case, Business Case and initial architecture, you have to think about the data that's going to be generated. That's the 3 step in my opinion. IoT devices will generate a lot of data per second/minute/hours etc. Even if your device only generates one event/second, when you add up a lot of devices, the numbers will grow exponentially. So have in mind the following: "Is it important to capture and store all the data? Is it important to send all the data to the Cloud?". Usually, the answer is no. Usually the data can (and should) be summarized on the edge and then sent to the cloud. If you need to send it all to the cloud, then summarize it before storing if forever.

Imo, the 4th step is building the application. Now that you have all the other 3 steps done, you can build the app. Remember what's the intent of what you're building. The interface is only a part of what you're building. Sometimes the interface may be an app on your phone. Sometimes it will be a report like a BI. If it's the later, than you may use a reporting tool like there are so many available in the market. Building the interface should be simpler then. If you need to build apps for your app, I suggest trying to build simple interfaces first, and later making it pretty. Make it functional first.

As I mentioned before, this is already part of the application you created. One thing that this brings to attention is the type of connection. One thing I learned in the IoT world that's really important, is to think differently. Don't think that events happen sequentially, nor design your app so that the actions happen sequentially. IoT apps really need to process events in parallel and use call backs. This may not be familiar to a lot of people but you need to get familiar with it. What are events, what's parallel, asynchronous and distributed processing, what's call backs. That's my suggestion.

I believe it’s important to understand the difference between a solution and a tool. IoT as any other technology, should be seen as a tool. Within this context, the solution should be developed around resolving the customer needs. By understand their needs, a solution can be developed using IoT or many other technologies/tools.

Connect everything. That's the starting point. The starting point is not to pick the hardware, implement the logic, or get onto the cloud. In our highly connected economy the rules are different than in the previous industrial economy. The starting point is the mindset to "connect everything."