We use them every day without realising it. They’re in our phones, our cars, our cameras, and innumerable electronic devices. They’re called MEMS, and they’re the microscopic switches that allow our gadgets to become smaller, lighter and faster.
Micro-ElectroMechanical Systems (MEMS) are minuscule mechanical switches that control the flow of electricity. That may not sound very impressive, but that simple mechanism is what allows the tiny sensors and actuators in modern electronics to work — the accelerometer in your phone and Oculus Rift, the sensor in your car that controls airbag deployment, the head of your ink-jet printer, the gyroscope in your game console controller — these, and countless other devices are all dependent on MEMS.
They are, in essence, mechanical switches, the same kind that have been used for years. But their advantage comes from their incredibly small stature. MEMS typically measure between 20 micrometers and a millimetre and, as Chris Keimel, a Process Development Engineer at GE, explains in the video above, “For a switch operating on the order of microseconds [millionths of a second] The way to make a switch faster is, ironically, to make it smaller. If it’s smaller it has less mass, and when it has less mass, you can move it faster.”
That’s why the switch arm (the moving mechanical component of the MEMS) is typically less than the width of a human hair. Were it larger, it would be heavier and unable to oscillate as quickly. What’s more, switches on that scale aren’t subject to the limitations of classical physics like inertia and can be accelerated even further using electrostatic forces, thanks to their relatively large surface areas.
As the state of the technology continues to push towards miniaturized, commoditized electronics systems, these tiny switches will continue to play a big role in their development. And if they’re doing their job right, you’ll never even notice they’re there. [GE – Geek – Wiki – CSA]