Errors (not human errors, but literally error conditions) can happen very quickly even in simple Arduino projects. For example, an external library might sometimes fail to load data from memory due to unreliable hardware (like with the MPU6050). In this case, if you have a serial connection, you might see the error description printed there. But what if you have no serial connection because you are using your board without having a computer connected?

Using the LED and blinking in different patterns is not a great solution, because you have to know or find out what the patterns mean, but it is often the best solution available (and real hardware manufacturers often choose the same method!). In this blog post, I want to show a simple and somewhat elegant way to do this.

Here is the code:

Pretty self-explanatory! If you haven’t worked with header files (like error_handling.h) before: they are really simple. Before your code gets turned into binary for the Arduino, the content of the header file is placed at it’s corresponding #include. Simple as that. This way, we can define our error handling functions without cluttering our main program. The header file must be in the same directory as the main sketch. You can rename the main sketch, but if you rename the header file, you must also remember to change it’s #include for the new header name.