Learn to make a 2D capacitive contact sensor with ElectroBOOM
— August 14th, 2025
Mehdi Sadaghdar, higher generally known as ElectroBOOM, created a reputation for himself with surprising content material on YouTube filled with explosive antics. However when you get previous the meme-worthy shenanigans, he’s a genuinely sensible man that gives helpful and accessible classes on many electrical engineering rules. When you like your studying with a touch of over-the-top leisure, he’s your man. And in his most up-to-date video, he defined how touchscreens work by constructing a 2D capacitive contact sensor.
There are a number of touchscreen applied sciences in use at the moment and Sadaghdar explains three of them within the video: infrared grid (usually referred to as “infrared contact body”), resistive, and capacitive. However capacitive contact is the usual today, as it’s the most handy and versatile. Because the identify suggests, capacitive contact sensors work by detecting adjustments within the capacitance between electrodes. Your fingers alter that by a measurable quantity, so it’s easy sufficient to register a contact throughout a single driver/obtain electrode pair.
From there, you’ll be able to add lots of these pairs and prepare them in a grid of rows and columns, just like a keyboard matrix. The extra electrodes you’ll be able to stuff right into a touchscreen, the upper the precision. However as a result of fingertips are fairly large, there isn’t a lot sense in having an enormous quantity.
The worth in Sadaghdar’s content material, apart from the zany hijinks, is in how he conveys these ideas in an comprehensible manner. To hammer the purpose dwelling, he made a easy 2D capacitive contact sensor that is sort of a low-resolution model of what you would possibly discover in a smartphone. He constructed it utilizing simply an Arduino Nano board and a few copper tape on a chunk of paper.
If you wish to combine a customized capacitive contact sensor into your subsequent undertaking, watching the video is a good way to get a grasp of the basics.
