Introduction
Most developers spend their days in code that never leaves the digital world. But what happens when your software has to control real hardware (such as instruments, relays, switches) and make them work together for automated testing?
As an Integration Systems Engineer, I build applications with C# that directly connect with test hardware. In this post, I will share practical strategies for bridging software with hardware, what works, what fails, and why this space is very fascinating for developers.
The Challenge of Software-Hardware Integration
When you work with software alone, “bugs” often refer to failing tests or stack traces. However, with hardware involved, bugs could indicate issues with the physical device/instrument. For example:
- A relay that won’t switch
- An instrument that times out during a test
- A driver that acts differently based on the OS version
Automated testing relies on reliability and repeatability. If only 1 percent of test runs fail because of unstable hardware integration, then the entire credibility of the system is at risk. This is why well-planned integration is crucial.
It has to be perfect!
Why I use C#, TCP/IP, and FastAPI Together
- C# is great for designing Windows-based applications and GUIs, either using WPF or WinForms as the framework. Interaction with drivers that control the test hardware is more seamless.
- TCP/IP is essential for smooth wireless communication between the software and test hardware. It ensures flexibility due to its layered architecture, which prevents disruptions and also ensures hardware independence, allowing all kinds of networks and devices to communicate.
- FastAPI is a modern Python framework used to build HTTP-based services in APIs.
The C# application queries the FastAPI endpoint that helps retrieve information stored in the database needed in the test definitions. Once this is retrieved, commands (depending on the test type) are sent over TCP/IP to the test instruments. These commands will be structured, ensuring the test instruments are operated in the required order.
This architecture promotes modularity and even allows remote access.
Practical Integration Strategies
Plan for Hardware Failures
Hardware will inevitably fail, whether it’s due to loosened cables, power cuts, or hanging. Robust integration anticipates and deals with this accordingly with:
- Logging for each hardware device
- Timeouts being implemented
- Retries
- Isolation testing to troubleshoot the issue
Hardware Simulation for Testing
Having the hardware sitting on your desk isn’t the most practical approach, especially for CI/CD. The use of a mock implementation that mimics the hardware behavior could help tackle this issue. This helps to test the code logic without depending on the physical hardware instruments.
Lessons Learned from the Real World
- Instruments could behave differently depending on their timing, so the addition of delays could fix these timing issues.
- Logging saves the day, as when hardware fails, logs are pretty much the most reliable way to trace the issue.
- Software can only do so much, as sometimes the fix is a simple wire change or cable connection, and not a line of code.
- The skills learned from the automation of test systems are transferable to IoT devices, manufacturing automation, Mechatronic systems, and robotics, making one a versatile engineer.
Conclusion
Working at the boundary between hardware and software pushes developers to see things from a different perspective and think differently. It’s no longer just pushing code; it is also controlling real-world devices with a certain degree of unpredictability.
If you’re a software developer curious about the world of hardware, automated test environments are a really good place to begin, and I hope these lessons help you bridge that gap