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Tutorials

Creating a Capacitive Touch Slider Element

Overview​

A capacitive touch slider is a touch input element made from multiple conductive pads. As a finger moves across the pads, firmware can estimate position and create a smooth slider interaction for brightness, volume, menu navigation, and more.

In this tutorial, we'll build a slider footprint using multiple polygon <smtpad /> elements and cover them with solder mask.

Build the Slider Footprint​

The example below creates 7 interleaved diamond/rectangle polygon pads in one custom footprint. Each pad is exposed electrically as a separate channel (S1 to S7), but visually appears under solder mask as a clean touch area.

What coverWithSolderMask / covered_with_solder_mask Does​

  • In tscircuit JSX, you set coverWithSolderMask on each <smtpad />.
  • In generated PCB JSON, this is represented as covered_with_solder_mask.
  • This keeps the copper pad under solder mask instead of exposing bare metal.
  • For capacitive touch, this is useful because the user touches the solder mask surface while capacitive coupling still works through the mask.

Final Result​

This design produces a compact capacitive slider footprint made from repeated polygon pads arranged into a continuous touch strip. In PCB view, you get a smooth slider geometry with each segment separately routable to a sensing channel.