You Can Use Your Mac’s Trackpad As a Scale (but You Probably Shouldn’t)
I know that the term “life hack” can sometimes be synonymous with “useless advice.” Those jokes are decades old, and I try to keep that in mind when writing articles. So let me be clear: I don’t think you should use your MacBook as a scale. Although, of course, you can .
Ontario developer Chris Shah has created an app that turns any Mac trackpad into a scale. This isn’t a great idea in the kitchen, mostly because you don’t want to spill ingredients on your expensive laptop. But the app is called TrackWeight , and it’s just plain silly, and I love it.
Trackweight requires you to lightly press your finger down on the trackpad (this is because your Mac won’t activate the trackpad unless your finger or something else with capacitance touches it). The idea is to position your finger so that it doesn’t put any pressure on the trackpad at all. I had the best luck with it by lightly pressing my finger down on the trackpad but mostly resting it on the laptop. If you want, you can press the spacebar with your other hand to reset the weight, or simply place an object on the trackpad to measure it.
I tested this on a few items, including a bowl of blueberries, and it was within a few grams of error, comparable to my kitchen scale.
I also tested this with the standalone Magic Trackpad – it worked just as well and was perhaps a little more practical as a scale (but still not at all practical).
So why does this work? Your Mac’s trackpad has a built-in pressure sensor, which is primarily used to detect how hard you’re pressing, such as when using Force Touch. When you press and hold the trackpad to activate Search Up and other features, your Mac uses the pressure sensor to determine how hard you’re pressing.
According to the developer , there’s a hidden API on the Mac that allows apps to detect how hard you’re pressing the trackpad, and that’s what’s used to calculate the weight of an object. It’s a fun trick and a showcase for the unexpected technology built into modern laptops.