The one last thing to do is load some code onto the Trinket to use the INA219, wire it up to a load and measure some current!
The INA219 breakout guide has all the info you'll need to use your newly assembled circuit. Note that since the breakout you created does the wiring to the microcontroller for you, you can skip the steps on how to wire the microcontroller and go straight to the section on wiring the INA219 breakout into the load circuit. Once the wiring is done, you can follow the INA219 guide's Circuit Python code example to put the board to use.
While writing this article, I made a boo boo. I thought I was being smart and ordered the board before I was done with the guide so that it would arrive just in time to take pictures. As it turns out, since I was in a hurry, despite checking it several times, I missed the fact that I had the header for the INA219 breakout backwards because I didn't use the outlines of the original boards to check the layout of the headers.
Despite this frustration I was still able to make the board work by using a stacking header to elevate the breakout above the Trinket.
The point of mentioning this is to remind you that even someone who has been doing this for a while can and will make mistakes. The important takeaway is that, when you make something, you learn how it works in the process and when you break it, you're equipped to fix it. Don't let a fear of making mistakes keep you from doing something because everyone will make mistakes. Making mistakes doesn't matter; learning from them does.
Congratulations, you've made a circuit board! As I previously mentioned, the project for this guide is just the tip of the iceberg. You can use these same techniques to do anything from breakout adapters like we just did, to custom feather wings or bonnets based on breakouts, or whatever your heart desires! We're just getting started. If you have an existing project based around Adafruit or other open source hardware, try converting it into a PCB.
The next guide in this series will take what we've learned here and turn it up a notch. Stay tuned.