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Hi I was planning to build a capacitive touch circuit to control a concrete lamp.

Will the touch work through 8mm thick concrete slab. If yes please suggest best way.

Thanks in advance.

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  • \$\begingroup\$ RF comes to mind, but it will also be challenging. \$\endgroup\$ – winny Oct 21 '18 at 18:22
  • \$\begingroup\$ Trying things is good for learning... \$\endgroup\$ – Solar Mike Oct 21 '18 at 18:35
  • \$\begingroup\$ I don't know. I suspect not, but if it does it's because you use a large sensor -- at least 2 inches on a side feels right to me, but that's entirely a guess. If it works, people will have to lay their hand on the spot, not just touch it with a fingertip. \$\endgroup\$ – TimWescott Oct 21 '18 at 18:55
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Interesting problem. If the concrete is not cast yet you could try to place the capacitive sensors closer outside, so they don't have to work through 8mm of concrete, but perhaps with just 1 or 2 mm.

Other ideas:

  1. Ultrasound. Boat sonar transducers (eg. from Garmin) can be mounted inside the hull and "shoot through the hull". Maybe this scheme can also be done with concrete?

  2. RF and some kind of radar

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I think the techniques used by traffic sensors can work in your case. After all, they do work through many inches of asphalt. Induction loops look like a good bet.

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