A while back I bought the InvenSense MPU-6050 sensor in a “GY-521” breakout board from eBay. For a long time it sat quietly in my box of “possibly cool things to check in the future”. Recently, I decided to finally get to building a self-balancing robot and dug it out. As with almost anything from eBay, it came with no documentation.The MPU-6050 breakout boards are quite popular in the Arduino community and information was easy to find. Even too easy: it took me a while to sift through many partial, or "almost" working implementations before I found a relatively easy to use, clean and reliable set of instructions and Arduino sample code. So here it is documented for future reference!