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ChrisMarshallNY
Very cool, but I'd still probably just buy a cheap digital scale.
tln
No download link?
qwertytyyuu
Ah I remember being able to do this with the iPhone 6s
hn_throwaway_99
I think this is neat, but only in a Rube Goldberg machine sort of way. The instructions are:

1. Open the scale

2. Rest your finger on the trackpad

3. While mainting finger contact, put your object on the trackpad

4. Try and put as little pressure on the trackpad while still maintaining contact. This is the weight of your object

That is, the pressure sensors only work if it detects capacitance, so you need to be touching the track pad (but not too much!!) while weighing something.

saaspirant
I use a similar approach to weigh objects using gym weighing machine. It doesn't trigger unless there's skin touch.
pmxi
This is clever! and potentially useful too.

Have you done any testing to determine how precise and accurate this is? I suspect their must be a lot of variance between laptops, since this isn’t an intended use case.

alden5
The app isn't accurate at all, magic 8-ball of scales, anything you put on the trackpad it'll settle on a weight and give you a number but it'll be random. The app will accurately tell you how much force you're applying with a finger but when putting something else on it'll settle on a random number
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DonHopkins
Just what I need to roll the quantitative doobie.
qoez
Apparantely on safari there's touch strength so this should be possible to make for the web too, cool
thrownawaysz
Can someone compile a binary? Don't want to download Xcode just for that...
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theyknowitsxmas
Apple would've made an app a long time ago but would get sued after someone put a tire on it.
mig39
Very cool, Krish! Hi from Fort McMurray! I'm going to use this project as an example for a Computer Science class.
ynniv
Finally some hacker news
ivanjermakov
> TrackWeight utilizes the Open Multi-Touch Support library by Takuto Nakamura to gain private access to all mouse and trackpad events on macOS. This library provides detailed touch data including pressure readings that are normally inaccessible to standard applications.

How can something be available as a library but not as a native interface? Swift does not expose that API?

jordanmorgan10
Back when we had 3D Touch, there was UIForce which did this. I still lament the loss of 3D Touch to this day :-(
arm32
I must not use this for weed, I must not use this for weed, I must not use this for weed
jahantech
This is exactly why normal people call us geeks "weird". Keep bringing on the cool stuff!
mikpanko
Very cool. Curious: what is the minimum and maximum weight MacBook's trackpad can reliably measure this way?
alden5
It goes in gram increments and my laptop was able to read 7300g pressing as hard as i could, which I was surprised it would be designed to read that high, might go up to 10kg but I don't want to crack my trackpad lol. The actual measurements though are extremely unreliable. I've found it can't reliably measure anything, measuring a roll of tape gave me measurements from 70g to 700g, it always settled on a number but was different every time. Maybe the underlying data is more accurate but this API is definitely just designed for outputting the force of a finger. M1 MBP for reference
fnord77
What's the weight range it can handle? no mention of it and I don't want to dig through code
projektfu
Could it be used to provide gait analysis for your pet mouse?
subdev
How does one come up with this idea?
pavon
I love this, such a creative hack, and the wonderful irony that it only works when one has their finger on the scale.

* Not legal for trade outside of Ankh-Morpork.