MacBook Pro's Trackpad Transforms into a Portable Scale: Creator Modifies Trackpad, Reveals Open-Source Code, and Affirms Force Touch's Accuracy for Weight Measurement.
Introducing TrackWeight: A New Software-Only Scale Solution for MacBook Users
A Canadian developer named Krish Shah has recently unveiled an innovative application called TrackWeight, which transforms the Force Touch trackpad of an Apple MacBook into a digital scale [1][2][3]. This software-only solution can surprisingly handle weights up to 3.5 kilograms with a level of accuracy that is impressive for its kind.
TrackWeight leverages the pressure-sensitive sensors introduced by Apple in 2015 on MacBook Pro and 2016 on MacBook Air models. The app reads pressure data (already expressed in grams) and converts it into weight measurements locally on the MacBook without any additional hardware [1][3][4].
However, there are some limitations that users should be aware of:
- Continuous Finger Contact Required: The trackpad’s pressure sensor operates via capacitance detection, so the user must keep a fingertip gently resting on the trackpad throughout the weighing process. This is necessary to register pressure data but also means the finger's own weight adds to the measurement. Users are advised to rest their finger as lightly as possible to minimize this effect [1][2][3].
- Weight Range Constraints: While the app can handle weights up to about 3.5 kg, pushing it beyond single-digit kilograms is not recommended as it could potentially damage the laptop [2].
- Object Size and Material: Objects must fit entirely on the trackpad for an accurate reading. Metallic objects can potentially interfere with capacitive sensing, so placing a paper towel underneath them is recommended to avoid misreadings [2].
- Experimental Status: The app is labeled “experimental and educational,” meaning it should not be used for critical or commercial weighing applications where precise accuracy is necessary [2].
TrackWeight uses SwiftUI for its user interface and Combine for reactive data flow. The app code is available on GitHub under the open-source MIT License. Prior work by Takuto Nakamura (@Kyome22) and the Open Multi-Touch Support library were significant contributions to the development of TrackWeight.
The app should work with any Force Touch-equipped Apple laptop released in 2015 or later (MacBook Pro) or 2016 or later (MacBook Air). Despite the requirement for constant finger contact, TrackWeight has been demonstrated to be "pretty accurate" [5]. However, its accuracy is limited by the requirement to maintain finger contact and the physical constraints of the hardware, making it unsuitable for highly precise or heavy weighing tasks [1][2][3].
[1] https://www.krishshah.com/trackweight/ [2] https://github.com/krishshah/TrackWeight [3] https://www.hackingwithswift.com/read/1/2021/trackweight-turns-your-macbook-into-a-scale [4] https://www.apple.com/uk/macbook-pro/features/ [5] https://www.theverge.com/2021/1/18/22241442/apple-macbook-force-touch-trackpad-weigh-scale-app-trackweight-krish-shah
- Despite being an innovative software solution, TrackWeight might not be suitable for heavy weighing tasks as it requires continuous finger contact on the Force Touch trackpad, which can add to the weight measurement and potentially damage the laptop if pushed beyond single-digit kilograms.
- WhileTrackWeight can transform a MacBook into a digital scale, it's important to note that smartphones and other gadgets with pressure-sensitive screens could also potentially function as scales with the right software, showcasing the power of technology in transforming everyday devices.
