Good luck! I used a SS441R hall sensor. You don't need to use an ADC or anything like that since the output is the same level as what would be needed for GPIO

Good luck! I used a SS441R hall sensor. You don't need to use an ADC or anything like that since the output is the same level as what would be needed for GPIO and you can use an edge trigger interrupt to know when the state has changed. The accelerometer is a GY-521 breakout board. It was a little tricker to work with because orientation is important and they are sensitive. Different cycles on my washer result in different vibration patterns, and the "bulky" setting rests for several minutes with no motion. Overall, it's the one project which gets used the most and has saved us from having to re-wash stuff because it was forgotten and got kinda funky. Best of luck!