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i'm currently preparing some experiments about using Bluetooth in real life. And to make the data more vary, i need some materials that can really giving side effects to Bluetooth functionality. i've been trying simple test with concrete walls (~7 in) and wooden door (~3.5 cm) and they seems not giving significant change

after some research, i've found that Bluetooth use radio wave (https://en.wikipedia.org/wiki/Bluetooth), and after many search results later i only found this as the possible nearest explanation (How can I create hindrances to radio waves?) but they only explained conductive materials only

is there any material (other that conductive one, prefer common types that we usually found around) that can interrupt Bluetooth connectivity?

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  • $\begingroup$ A Faraday cage perhaps? $\endgroup$ – Phoenix87 Jul 15 '15 at 14:05
  • $\begingroup$ A Faraday cage uses conductive materials. $\endgroup$ – Jon Custer Jul 15 '15 at 14:13
  • $\begingroup$ The precise reason that Bluetooth uses the frequencies it does is that A) it isn't harmful to humans, B) it isn't a restricted band, and more importantly C) there aren't many common materials around that easily block it. So you won't find any common household materials that block bluetooth signals effectively, by design. Making a Faraday cage is perhaps your only option $\endgroup$ – Jim Jul 15 '15 at 14:37
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    $\begingroup$ Why do you say that conductive materials are not common types. Many buildings today use steel studs and girders in construction. I routinely have difficulty with cell phone reception in my office. I have to go to the hallway. I know OP asked for non-conductive, but his reason is flawed. $\endgroup$ – Bill N Jul 15 '15 at 15:03
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Such a material (apart from conductive ones) typically doesn't exist. The reason: when a material is interrupting bluetooth, it's either reflecting or absorbing the radio wave. Reflective materials are also absorptive materials, so this comes down to finding a material that absorbs radio waves.

For metals and other conductive materials, electrons are very mobile, and act as the absorbers. For non-conductive materials, absorption tends to be a quantum phenomena. The energy of a single photon must be the same as the transition energy from a quantum base state to an excited state. These energies tend to be much higher than the energy of a radio frequency photon, meaning you won't find any material that absorbs radio waves that isn't also conductive.

Your best bet is either a metal or a thick partially conductive ceramic to block the bluetooth. Concrete is one example, but you'd need a very thick piece. You'd also have to ensure that the concrete is large enough such that the wave won't refract around it.

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The problem is basically that radio waves are big and tend to be able to "curve around" and "penetrate" obstacles. Metals and conductors will be the hardest things to get around/through. So maybe your problem is that you're just putting, say, one concrete block between two bluetooth devices, rather than a whole concrete wall.

You could try metal and ceramic sinks, or a Faraday cage of aluminum foil, to get near total wrapping around the thing. You could compare the tin-foil one to what happens when you stick the receiver in a microwave, or a locker, or a safe.

You could try to put it in a "bunker" made of bricks/blocks/sandbags.

Probably the most interesting thing would be to fill some sandwich bags with water and stack water into a similar bunker. You could then see if freezing the bags solid changed anything, testing out an igloo.

You could test dirt by digging a hole. It might be interesting to know how deep you could be buried alive in a coffin that you could still call someone to come rescue you.

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    $\begingroup$ Coffins usually have a structure made out of metal. So..... it would act as some sort of Faraday's cage, greatly reducing cellphone signal penetration within. $\endgroup$ – Gummy bears Jul 15 '15 at 15:41
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I've found that my plaster lathe walls, combined with conduits in the ceiling for the light fixtures, block almost any wifi or bluetooth penetration from one room to another - I can get wireless signals through one wall only, because the plaster's been replaced with wood paneling on both sides of that wall.

This has caused me to pay hundreds of dollars for hard wired RG6, RJ45, and 3.5mm connections in each room, run under the house in the crawl space.

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    $\begingroup$ While this sort of answers the question, it is all rather anecdotal. This is Physics.SE, so generally there should be some explanation grounded in physics in an answer. $\endgroup$ – Kyle Oman Aug 10 '16 at 16:41
  • $\begingroup$ My hypothesis is "Faraday cage effect", but I have no idea how I would go about proving or disproving that. $\endgroup$ – Aging Hippie Sep 15 '16 at 20:00

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