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What is capacitive sensing

This is how the Touch Board and the Pi Cap work, but what does it really mean?

graphic showing capacitive sensing

The capacitive sensors of the Touch Board and the Pi Cap use capacitive sensing. But what exactly is capacitive sensing? And what other technology uses capacitive sensing? This tutorial gives you a brief oversight about this amazing technology.

How do capacitive sensors work

Capacitive sensing is a proximity sensing technology. Capacitive sensors work by generating an electric field, and detecting nearby objects by sensing whether this field has been disrupted. Capacitive sensors can detect anything that is conductive or that has a significantly different permittivity than air, like a human body or hand.

Permittivity is the measure of how difficult it is to create an electric field around a material. It’s the ability of a substance to store electrical energy in an electric field.

The Touch Board and the Pi Cap have 12 capacitive sensors each. Every sensor can individually detect touch and proximity.

illustration of what is capacitive sensing

Where else is capacitive sensing used

Capacitive sensing is all around us. It’s the same technology used by smartphone screens to detect touch. It’s also used in other applications where there’s a need to detect human touch. It’s a very useful technology when detecting proximity, when trying to detect something without directly touching it.

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