There is a bit of a paradox when it comes to miniaturization. When electronics replaced mechanical devices, it was often the case that the electronic version was smaller. When transistors and, later, ICs, came around, things got smaller still. However, as things shrink to microscopic scales, transistors don’t work well, and you often find — full circle — mechanical devices. [Breaking Taps] has an investigation of a MEMS chip. MEMS is short for Micro Electromechanical Systems, which operate in a decidedly mechanical way. You can see the video, which has some gorgeous electron microscopy, below. The best part, though, is the 3D-printed macroscale mechanisms that let you see how the pieces work.
Decapsulating the MPU-6050 was challenging. We usually mill a cavity on the top of an IC and use fuming nitric on a hot plate (under a fume hood) to remove the remaining epoxy. However, the construction of these chips has two pieces of silicon sandwiched together, so you need to fully expose the die to split them apart, so our usual method might not work so well. Splitting them open, though, damaged parts of the chip, so the video shows a composite of several devices.
The parts inside are microscopically small. It took a week to trace everything out and make the 3D-printed macroscale mechanisms that help explain how each piece works. Seeing a model of the accelerometer that is large enough to handle in your hands is very helpful in understanding how they work. You can build your own but be warned: the clearances are very tight, so you need a well-calibrated printer.
Like anyone who makes content, it is easy to find people to correct your mistakes, and [Breaking Taps] did have a minor misspeak you can read about in the first pinned comment. But the error is small, and we predict unless you are an expert MEMS designer, you’ll learn something new by watching this video.
Your phone isn’t the only beneficiary of these tiny mechanical devices. We’ve seen, for example, digital levels. Self-balancing robots come to mind, too.
Thanks to [smellsofbikes] for the tip!