The concept of sharpening a knife — dragging it along a surface at an angle to create an edge — isn’t hard to grasp. What is hard, however, is dragging it over and over at exactly the right angle in order to create a blade sharp enough to cut fruits and vegetables like the blade is sliding through silk.
While most of us are content to mangle an apple once in a while, this wasn’t good enough for Alex of Alex French Guy Cooking, who teamed up with Becky Stern to make a sharpening angle coaching device.
After a conversation with Alex about how this could be done, she came up with something that attaches to a knife with powerful magnets and measures the angle using a BNO055 9-DOF absolute orientation sensor. This data is then transferred wirelessly via Bluetooth to a mobile device to indicate whether the blade is being held properly.
In an interesting twist on how technology is normally used, the point of this device is to eventually work itself out of a job, training a human’s muscle memory to sharpen without the need for technological assistance. Be sure to check out a video of Stern’s build in the video below, along with the corresponding clip of Alex making and trying out his own electronic coach based on her instructions.