Gesture-Detecting Macro Keyboard Knows What You Want

[jakkra] bought a couple of capacitive touchpads from a Kickstarter a few years ago and recently got around to using them in a project. And what a project it is: this super macro pad combines two touchpads with a 6-pack of regular switches for a deluxe gesture-sensing input device.

Inside is an ESP32 running TensorFlow Lite to read in the gestures from the two touchpads. The pad at the top is a volume slider, and the square touchpad is the main input and is used in conjunction with the buttons to run AutoHotKey scripts within certain programs. [jakkra] can easily run git commands and more with a handful of simple gestures. The gestures all seem like natural choices to us: > for next media track, to push the current branch and to fetch and pull the current branch, s for git status, l for git log, and the one that sounds really useful to us — draw a C to get a notification that lists all the COM ports. One of the switches is dedicated to Bluetooth pairing and navigating menus on the OLED screen.

We love the combination of inputs here and think this looks great, especially with the double touchpad design. Be sure to check out the gesture demo gif after the break.

Gesture input seems well-suited to those who compute on the go, and a gesture glove feels like the perfect fit.

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Tensors Explained

You can do a lot of electronics without ever touching a tensor, but there are some situations in which tensors are absolutely essential. The problem is that most math texts give you a very dry description that is difficult to internalize. That’s where [The Science Asylum] comes in. Their recent video (see below) starts with the dry definition and then shows you what it means and why.

According to the video, the textbook definition is:

A rank-n tensor in m-dimensions is a mathematical object that has n indices and mn components and obeys certain transformational rules.

That sounds a lot like an array but we are not sure what “certain transformational rules” really means to anyone.

Wikipedia does a little better:

[A]n algebraic object that describes a linear mapping from one set of algebraic objects to another.

These constructs are key to anything electromagnetic (including antennas) and show up a lot in stress calculations and quantum mechanics. Even Einstien’s theory of relativity uses tensors.

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