Introduction: Faraday Cage Phone Pouch

Picture of Faraday Cage Phone Pouch

This Faraday Cage phone pouch blocks all radio signals coming in or out of your cellphone. Material costs are about $10, it takes ~ 30 minutes to build, and it can fit in your pocket!

The purpose of this pouch is to prevent access to your phone and its data (e.g. location) if and when you so choose. Before placing your phone in the pouch, be sure to put it in airplane mode as the phone will drain its battery trying to find a signal.

Check out this video if you want to learn more about Faraday Cages!

Step 1: Materials

Picture of Materials

-- Conductive fabric

Sized to fit your phone + a top flap. For an iPhone w/ a (giant) case, I needed about 7.5" x 3.5".

-- Thread (regular, any color)

-- Button (any type)

Alternatively, you can use velcro, a safety pin, or any other means to hold down the top flap.

Step 2: Tools

Picture of Tools

-- Scissors

-- Ruler

-- Needle or Sewing Machine (preferred)

-- Safety pins (optional but helpful)

Step 3: Build It! Pt. 1

Picture of Build It! Pt. 1

1. Measure the width, height, and depth of your phone (+ case, if you have one).

2. Add 1" to your phone width measurement and 2" to your phone height measurement. Cut conductive fabric into a rectangle of that size.

For example, the iPhone 5 is 4.87" tall, 2.31" wide and 0.30" thick. Thus, you want a rectangle that is at least 6.5" tall and 3.5" wide.

To double check your measurements, mark where you plan to cut the conductive fabric w/ a pen or pencil. then wrap the fabric around your phone. Be sure that you can fold down the top of the conductive fabric.

Helpful tip: It's always better to leave extra room. Measure twice, cut once, and so forth.

3. Place phone on one side of the conductive fabric and fold the fabric over the phone. Safety pin sides together.
Leave an inch or two above the phone so the top can be folded over like an envelope.

Step 4: Build It! Pt. 2

Picture of Build It! Pt. 2

1. Sew bottom + sides of conductive fabric together using small hand stitches or a sewing machine.

2. Turn pouch inside-out to hide stitching.

3. Place phone inside pouch, fold top down and mark where the button will go.

4. Sew button on & cut a small slit in the top flap to attach.

Remove excess fabric as necessary, but be sure that the conductive fabric completely encases the phone when the top flap is folded down.

Step 5: Done!

Picture of Done!

Place phone inside the Faraday Cage pouch whenever you want to cut off all radio signals coming in and out of your phone.

For another awesome version of the same concept, check out my friend's scarf project here.

Curious as to how this works? Awesome! In super simple terms, a Faraday Cage "traps" radio waves in the wires that make up the cage. In this design, the conductive fabric threads are the metal wires that form the Faraday Cage. Due to the small mesh size (aka wires are super close together), this design will block any electromagnetic radiation with a wavelength larger than visible light. :)

Here's a good overview on what a Faraday Cage is and how you can build a different version.

And here's the Wikipedia blurb on Faraday Cages, an excellent source if you want to learn more!

Comments

Celeste Patin (author)2015-04-28

nice work

jenfoxbot (author)Celeste Patin 2015-05-04

Thanks!

Toofle (author)2015-05-01

Hi. I got a jacket made from conductive textile for working in a factory with small elektronic components. wheb i wrap my phone inside the jacket i can still make calls. Nothing get cancelled out. Is the textile not dense enough?

jenfoxbot (author)Toofle2015-05-04

Interesting question! Any air gaps in the fabric will allow radio signals to pass through. Try folding the phone into the jacket and smoothing out any wrinkles. If it still receives calls, then it likely has to do w/ mesh size.

philip.williams.7505 (author)2015-03-29

This is a great idea. Could this be scaled up for PC's and the like?

Thank you!

Re: scaling up: Yes, absolutely! In fact, I used to work in a building that was an (accidental) Faraday Cage, and it effectively blocked all incoming radio waves. As long as you maintain sufficiently small mesh size (gaps b/w the wires) and have a full enclosure, you can make it as large or as little as you'd like.

Great! Thanks for the information and the project! Keep up the good work!

Happy to help :) & thank you v. much!

parvgupta001 (author)2015-02-20

AWESOME INSTRUCTABLE M LOVING IT

jenfoxbot (author)parvgupta0012015-02-24

Thank you!

sgeorge22 (author)2015-02-08

Have you tested it?

jenfoxbot (author)sgeorge222015-02-08

Yup, many times. Calls/texts/e-mails/etc. do not go through while the phone is in the pouch and the top is closed. You'll receive texts/voicemails/emails when you take the phone out, although you will not receive a "missed call" notification.

tytower (author)2015-02-07

I didn't know my phone keeps searching for a signal if it does not have one.

Wouldn't a metal box do the same thing?

jenfoxbot (author)tytower2015-02-08

Yes, a metal box will do the exact same thing (as long as it has a lid), but that's less likely to fit in your pocket! :)

rdaly4 (author)2015-02-07

I always enjoy your presentations . Very well thought out .

jenfoxbot (author)rdaly42015-02-08

Thank you v. much!

mmmelroy (author)2015-02-06

super neat! nicely documented and great informational links for the less informed amongst us

jenfoxbot (author)mmmelroy2015-02-06

Thank you! Glad you found it helpful :D

tomatoskins (author)2015-02-05

I love conductive fabric! I'd suggest placing the phone into airplane mode before sliding it in. If not, your battery will suffer while continually trying to find a connection with a tower. Great Project!

jenfoxbot (author)tomatoskins2015-02-05

Thanks! Yea, I made that disclaimer on the intro page.

juanvi (author)jenfoxbot2015-02-05

what is the difference grom airplane mode to aiplane mode + faraday cage?
btw good intructable you had a nice idea

jenfoxbot (author)juanvi2015-02-05

Thank you! And excellent question! One reason is to ensure that when you want your phone to be off, it is actually off. This means absolutely zero data coming in or out of your phone. Unfortunately, turning your phone on airplane mode, or even turning it off, does not eliminate all of the data going out of your phone. For example, a friend of mine discovered that all phones constantly send out location data. Most of this data is used harmlessly, like calculating commute times and giving us traffic info. However, I am an advocate of personal privacy, and I want to control who has access to my phone. If I ever want to know for certain that no one else is accessing my phone and its data, I can put it in the handy dandy Faraday Cage pouch :) Maybe I'll even make one for a laptop!

Here's a link to the article about the location data issue: http://www.wsj.com/articles/SB10001424052748703983704576277101723453610

skrew_dreyever (author)jenfoxbot2015-02-05

i think this is a very well instructions instructable and it looks really cool too! having said that, however, I am not sure that this pouch blocks radio and data signals. I was under the impression that a Faraday cage device blocks electromagnetic waves from harming the electrical device inside. I am sure that it could also block radio waves as well, I just haven't read up on that yet. Also, I am pretty sure that putting your phone on airplane mode will effectively TOTALLY cut you off from being able to send or receive ANY signals, at all, be it directly such as when you attempt to send a text, check email, or watch a youtube video or indirectly such as if you have a weather app and it tells you how many feet of sunshine you can expect that day. airplane mode cancels all of that and simply allows you to use your phone as a pocket watch or calculator or gameboy. taking it off of airplane mode and you can send and receive texts. turn on the data button or wifi and you can get the latest weather or look at new instructables. if you are getting traffic reports while in airplane mode then I would really appreciate knowing how because my data plan is killing me.

jenfoxbot (author)skrew_dreyever2015-02-06

Thanks for the feedback! First, all data sent in/out of your phone is some form of a radio wave. Radio waves are electromagnetic radiation, just w/ a lower frequency + longer wavelength than visible light.

Second, rest assured that all electromagnetic radiation with a wavelength larger than visible light is blocked by this pouch, as long as there are no air gaps. This is because science. Yay, science! I linked a couple of good articles that cover what a Faraday Cage does at the end of this tutorial, I highly recommend the Wikipedia article.

Third, I'm not so concerned about data I am requesting, as data that is being requested of my phone. Location services, including the issue I mentioned above, do not necessarily turn off when your phone is in airplane mode. In fact, some airplane modes do not turn off GPS services. If you are still unsure about this, I encourage you to read the article I linked above, or do some research on your own. Here's a good article to start: http://www.howtogeek.com/194421/what-does-airplane-mode-do-and-is-it-really-necessary/

When in the pouch, this Faraday Cage case eliminates all access to your phone and its data, guaranteed. Please let me know if you have any more questions!

skrew_dreyever (author)jenfoxbot2015-02-06

cool, thank you!

jenfoxbot (author)skrew_dreyever2015-02-06

You're welcome! :D

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Bio: Dabbled in dark matter, settled into engineering with a blend of inventing and teaching, always trying to solve problems + learn new things!
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