MacBook Pro Trackpad Functionality Expanded: Now Serves as a makeshift Scale, with the underlying code accessible to users - innovator modifies trackpad for weight measurement, boasts Force Touch technology's precision.
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The TrackWeight app, a new addition to the macOS ecosystem, offers an innovative solution for weighing small to medium items using the Force Touch trackpad of Apple MacBooks. Developed by Canadian maker and blogger, Krish Shah, this open-source application has reportedly shown surprising accuracy, with successful measurements up to 3.5 kg[3][4].
How TrackWeight Works and Accuracy
The app measures pressure via the MacBook's Force Touch sensors combined with capacitive touch data, converting force readings into grams[1][2]. To ensure accuracy, users must maintain finger contact on the trackpad during weighing. While this requirement slightly affects accuracy due to the added pressure, it allows the capacitive sensor to detect pressure accurately[2][3].
Accuracy was tested by comparing TrackWeight's readings against traditional scales, showing a good match, confirming its ability to function as a tiny scale[1][3].
Key Limitations and Potential Issues
The TrackWeight app has several limitations that should be considered.
- System requirements: macOS 13.0 or later and a MacBook with a Force Touch trackpad (2015 or newer MacBook Pro, 2016 or newer MacBook)[1][2][3].
- App Sandbox must be disabled: The app requires disabling macOS’s App Sandbox to access low-level trackpad data, which is a security trade-off[1][2].
- Finger required during weighing: The need to keep a finger on the trackpad limits convenience and potentially alters weight readings slightly due to added pressure[3][4].
- Sensitivity to material: Metal objects can interfere with capacitive sensing, so it is recommended to place a paper towel under metallic items to avoid misreadings[1][3].
- Weight range: Best suited for items from a few grams up to a few kilograms. Weighing very heavy items (e.g., bodyweight or large luggage) is not recommended, with risk of damaging the MacBook trackpad[3].
- Experimental use only: The app is intended for educational and experimental purposes, not for commercial or mission-critical measurements that require exact precision[3].
Summary
The TrackWeight app is fairly accurate for small to medium weight items and cleverly leverages the MacBook's Force Touch hardware. However, limitations like the necessity of finger contact, sensitivity to metal, required system modifications, and restricted weight range mean it’s best used as a novelty or backup scale rather than a professional measuring tool.
The app’s source code is openly available on GitHub, enabling community scrutiny and improvement[2]. It's important to note that the app should not be used for weighing 'mission-critical' substances, commercial purposes, or when weights and measures precision is essential.
The app uses the Open Multi-Touch Support library, which provides access to global multitouch events on macOS trackpads, as an important contribution[5]. The user interface was developed using SwiftUI, and for reactive data flow, the app uses Combine[6]. The app was released under the open-source MIT License.
[1] - TrackWeight on GitHub [2] - TrackWeight on Krish Shah's Blog [3] - TrackWeight on Hackaday [4] - TrackWeight on Wired [5] - Open Multi-Touch Support on GitHub [6] - Combine on Apple Developer
Gadgets like the TrackWeight app showcase the innovation possible with smartphones and technology, as it transforms MacBooks into miniature scales. The app displays impressive accuracy by utilizing the Force Touch trackpad and capacitive touch data, but requires a finger to remain on the trackpad during weighing to ensure accurate readings.
