Apple first announced the iPhone 4's gyroscope at WWDC 2010, but it was largely overshadowed by other big players inside the phone -- the A4 processor, Retina display, and external antennas. A lot of technology gets stuffed into vibrational gyroscopes (the type found in the iPhone 4), yet a casual observer may barely notice the chip itself, let alone the phenomenal contents within it. iFixit and Chipworks have partnered to show you exactly what's inside these little gems.
Vibrational gyroscopes have a ton of practical uses, including automotive yaw sensors, game controllers, and image stabilization in cameras. Now, iPhone 4 applications and games can also benefit from their superb accuracy. The teardown covers not only the iPhone 4's gyroscope, but vibrational gyroscopes in general. We tried our best to explain how vibrational gyroscopes function and have documented their internals at a microscopic level.
Some of their findings:
- The iPhone 4 utilizes a microscopic, electronic version of a vibrational gyroscope, called a MEMS gyroscope.
- A microelectromechanical system (MEMS) is an embedded system that integrates electronic and mechanical components at a very small scale.
- A basic MEMS device consists of an ASIC and a micro-machined silicon sensor.
- The AGD1 2022 FP6AQ chip found in the iPhone 4 is a MEMS gyroscope rumored to be designed by STMicroelectronics.
- Chipworks has confirmed that the MEMS gyroscope found inside the iPhone 4 is nearly identical to an off-the-shelf STMicroelectronics L3G4200D gyroscope.
- The picture (above) is that of the GK10A MEMS die, found in the L3G4200D.
- The GK10A is comprised of a plate, called the "proof mass," that vibrates (oscillates) when a drive signal is applied to set of drive capacitor plates.
- When a user rotates the phone, the proof mass gets displaced in the X, Y, and Z directions by Coriolis forces. An ASIC processor senses the proof mass' displacement through capacitor plates located underneath the proof mass, as well as finger capacitors at the edges of the package.