The inner-workings of Apple’s Force Touch trackpad revealed

TrackpadIconXIf you are interested in the Force Touch trackpad on Apple’s new MacBook, iFixIt has performed a full teardown of the new system to reveal its underpinnings, and in doing so has outlined some of how the trackpad works. Apple’s trackpad brings several key advancements to its input technology, and while it may not fit everyone’s tastes, it should help overcome a number of limitations to Apple’s current trackpads. 

Overall the trackpad consists of three separate parts. First, it contains a similar capacitive multi-touch trackpad similar to other MacBooks. Underneath this, the pad has a rigid frame that connects it to the new layers of technology (a deflection detector, and a feedback buzzer) that make this new trackpad so unique.

While in other trackpads there may be one or more buttons that will click when depressed, the new trackpad’s frame rests on four strain sensors. These sensors each contain an array of parallel circuits on a flexible support that slide against a sensor when depressed, allowing the system to detect a minor deflection from a greater one. As a result, unlike a button that gives an all-or-nothing response, these sensors provide graded feedback that the system can use for various purposes.

Being that the new trackpad essentially floats on these flexible pads, the system can combine the inputs detected on each and weigh them against each other to determine how much total pressure is being applied, and where. For instance, when pressed in the middle, all four pads will flex evenly, whereas by pressing on a corner, the one under that corner will deflect more. The system can then determine if you are intending a standard button press, or another of Apple’s supported force-based gestures.

Apple's force-touch trackpad

The cross-like support under the trackpad surface (left) evens out pressure to the four sensors that it rests on (right). The orange components contain fine conductor arrays that are part of the flex-sensing unit (image credit:

Since Apple has removed a classic button, it has built in a new Taptic engine, which is essentially a small electromagnetic buzzer (similar to that of a tattoo pen) to provide the necessary feedback you need. As you press, if the system detects you intend a button press, then it will give you a buzz that mimics the feel of a classic button action; however, in addition it can provide its own graded responses, and give you tactile feedback for any action, such as when moving items or when errors display, or if you drag an item and your cursor hits the edge of the screen.

These improvements amount to an ability to use the trackpad somewhat like a Wacom tablet, where the system can not only pinpoint input location, but also pressures, to provide a number of new input options. Just imagine tapping and dragging your windows around by not even lifting your finger. This makes management similar to how you would shuffle photos around on a flat table surface. In addition, the feedback options give you the possibility of far more interaction with your system. Granted at first these behaviors will be limited and may need some tweaking, but over time it should prove to be a solid improvement to how we use our Macs.

To take a closer look at this trackpad, the folks over at iFixIt have included some nice close-up shots of the system, along with what it takes to disassemble and potentially service the system.

2 thoughts on “The inner-workings of Apple’s Force Touch trackpad revealed

  1. B. Jefferson Le Blanc

    With a trackpad so pressure sensitive, you will need fingers equally pressure sensitive. Not to mention what pressures do to what objects on screen. At a minimum it will take getting used to. But I suspect a year from now these Force Touch trackpads will be showing up on other Mac laptops. I will be interested to see some reviews of just how well these “innovations” actually work. Do they simplify things (I doubt it) or make them more complex (probably). Not to mention the “one port to rule them all” on the new MacBook.

  2. NYMike

    I’m wondering if these innovations will eventually migrate to Apple’s stand-alone trackpads.

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