Disabling Your Cell Phone’s Mic For Security


[Dan] set up this simple cell phone hack to disable his microphone when he’s not using his cell phone. He had read that the government can listen to you using your cell phone, even when it is off. This concerned him enough to hack into his phone. He removed the expansion port and wired the microphone to a magnetic reed switch. A strong magnet located in the screen side of his flip phone opens the circuit when he closes the phone. He notes that you could always just pop the battery out of your phone, but then you are left completely disconnected. This mod allows you to still receive phone calls.

114 thoughts on “Disabling Your Cell Phone’s Mic For Security

    1. Anybody with the knowhow can hack into a computer these days can hack a cell phone because it typically has a computer operating system installed and regardless of the operating system the processes for hacking it are pretty much the same. (you can even install Android, one of the most popular cell phone operating systems, on your laptop as an operating system if you desire to do so, do a search for Android X86 to confirm) This means anybody who has enough desire can hack into your cell phone or other devices and listen in on your conversations as well as use the background noise to better determine where you are, this has been going on long before there was paranoia over the possibility.

      Having said that, not all people who desire privacy are conspiracy theorists or paranoid. In fact, most who are concerned about that subject simply want to keep personal things personal and private conversations with friends and loved ones private. I mean, if somebody you know trusts you with something they want to talk to only you about, you would not want others overhearing it and then passing that information on to others. If you know that everything you say will be heard by people you do not know you will be more likely to keep what you want to let out with somebody you can confide in to yourself and bottle it up inside which will lead to worse psychological issues later.

      There is also a more obvious aspect of this: if there are cameras and listening devices everywhere then nothing you say or do remains between you and people you trust. If there are cameras and microphones in every room you eventually find yourself being more careful of what you say and changing your actions to not look out of the ordinary. This is why putting a camera at the front of a store or building and making it as obvious as possible is a good deterrent to shop lifting and violence, if people know that their every action is being recorded you do not have to do much to control them because they will force themselves to not act out of the ordinary.

      That being said, if you have devices that are constantly watching and listening throughout your home and everybody is carrying something that is recording themselves and everybody around them, there is no such thing as privacy anymore. This means that you will never feel that you can have a space to be yourself for even a moment and this can be psychologically damaging, especially to those who do not fit in with the majority to begin with. Of course eventually those who do not fit in will adapt and change themselves to fit in, but invention and new ideas tend to come from those who do not think or act like the rest of us so our growth as a culture will be stunted.

      Notice that I had not mentioned the governments, businesses, agendas or 1984. The focus of this post is to explain why having cameras and listening devices recording you is not a good thing. Feel free to offer up any counterpoints but let’s leave the insults by people who do not even research news articles out of it.

    1. What are you a frickin fed? Why would you try to give the impression this is conspiracy theory or a paranoid idea. It has been in major newspapers and regardless of what a sell out judge says, it is wrong. The government has no right to listen in and if they are so afraid of the people maybe they should start acting right.

    2. Congratulations, dickcheese! We have been proven right. Snowden, PRISM, the major companies out there fucking us over. Here, you can have this piece of tin foil and stick it up your retarded ass.

  1. Just because you are paranoid doesn’t mean everybody isn’t out to get you.

    Seriously dude, nobody gives a crap about what you are talking about.

    Get over yourself.

    If “they” want to listen in on you or know where you are or what you’re doing, “they’re” pretty much going to do it.

    You know, Black Helicopters, Major Leauge Baseball, the whole she-bang!

    koo koo

    koo koo

  2. srsly. Unless you warp back to like 1970s and become totally disconnected, they can find anything they want about you. Your whole life is online now, no matter how hard you try to maintain a facade of “privacy”. And TBH, I sometimes like to throw in random phrases like “the bread is in the oven” just to fuck with anyone who might be listening.

  3. I was just about to post my own snarky tin-hat joke until I followed the second link in the piece. Seems that this form of wiretapping has actually been done. This hack isn’t as crazy as I originally thought. I agree that the average joe would have to be paranoid to worry about this, but I don’t think it’d be too terribly nuts for certain types of activists, criminals, terrorists, freedom-fighters, etc. to give this a shot.
    Also, the magnetic reed switch is kinda clever– Having a mini-toggle hanging out of your cell would be pretty annoying.

  4. >>”Also, the magnetic reed switch is kinda clever– Having a mini-toggle hanging out of your cell would be pretty annoying.”

    I have to agree with john here. Whether I think the guy is crazy or not, the hack is the heart of the matter. I for one would never have considered a reed switch for this at all. That just isn’t where my mind would be. I’d like to see this incorporated into a project involving doors in home automation or something like that.

    Also, don’t make fun of the foil hat. Mine is very stylish.

  5. The simplicity of this hack is exemplary. Very nice.

    As for those that think this is paranoid, it isn’t the government that you need to worry about. They don’t care about you, but others may. This kind of wiretapping is even available as a commercial service for parents to listen to their kids phones for gods sake.

    It is also commonly used by ex’s looking for things in settlements, employers, competitors, etc.
    I have had a girlfriend whose phone was tapped, most likely as her dad was an exec in a company targeted for a buyout at the time. Competitors do this. Crummy lawyers do this. Your company can do it to you. Your ex or your favorite stalker can, too, and will.

  6. well for his work i love it good for you for thinking out of the box and if you do have the gov listening in on you Just remember you just made it that more difficult for them to do there job and anyone that does that brave o screw HLS

  7. Hi!

    I´m wondering what good is it for doing such hack to an old Nokia series40 phone.. those cannot run any hidden listening-applications..

    I must say though that using a reed switch like that in a phone like that is very clever..

  8. Wow, talk about paranoid… and stupid. If they really want to listen to you and you do this to your phone, it just gives them another reason to be suspicious and try harder. Ever think of that?

  9. Meh hate all you want but this is the first hack ive seen on hackaday in a long time thats as ingenious but simple as this, using the mechanisms of the device itself to switch it on and off with the minimum of parts is what hackings about! not making completely new products with microchips let alone arduinos, id almost call lego mindstorm not hacking if it wasn’t for the simple cool factor of lego!

    1. there were some lovely foil hats above – you may wish to check out ZELDAdog’s a number of comments above – possibly if you reply to their thread they might let you know the designer of their lovely stylish foil hat.

  10. So we can have no reasonable expectation of privacy any more? Just give up, and let the government have any information they want?

    Everyone saying this guy is paranoid, is going on to say “they” already know everything. That sounds pretty paranoid to me..

    This a great hack. Kudos! I wish I could do something similar with my iPhone.

  11. It doesn’t hurt to be a bit more secure. As Stunmonkey said, you can download applications that run silently in the background to do these sorts of things (saw one for the blackberry).

    You still need physical access to the phone, but that wouldn’t be hard for a spouse to do.

  12. “they” being to hear what you say when the phone is off == “they” are standing near you? In which case, this will do diddly shit unless the reed-switch somehow emits some sort of privacy bubble.

    It’s weird that people that have nothing worth wire tapping get all upset about it whereas government officials etc don’t seem to give a shit at all (plaintext passwords over Tor etc).

  13. Maybe they thought of this, and have another secret microphone embedded in the processor(with a dedicated super battery that lasts at _least_ 9 years)! better throw it in the microwave to be save.

  14. Wow, what a bunch of pricks today… slick hack, I like the use of the reed switch… and for those who think this sort of thing is for crazy people…. google preemptive detention and see what Obama has in store for American citizens…

  15. If it’s been confirmed by the feds it’s no longer paranoia, now you could argue they might not target him, but seeing AT&T allowed the NSA to listen in on like a hundred million subscribers too, well, there’s that, and you and I don’t know what this guy making the hack is up to, perhaps he does something completely reasonable that certain parties don’t like, or perhaps he buys some weed once in a while, point is that there is NO reason to say it’s paranoia or to attempt to be so out of the loop as to make jokes as if it’s not done.

    I find it quite incredible how so many americans manage to completely ignore facts and reality and go as far as to try to ridicule people that don’t, you are ridiculing yourself at that point.

  16. OK, people who think I am paranoid are missing the point. If I was paranoid I never would have put this up on my web page, would I? My point was that if people get in the habit of just shrugging their shoulders to such things then we are in big trouble.

    To those who think that there is nothing to worry about I have three things for you to look up: COINTELPRO, Josepy McCarthy, and China. Maybe right now in this country it doesn’t matter to the majority of the people, but that is just because we are lucky to live in this country and in this time period.

  17. Most humans are the Eloi just asking to be harvested by the Morlocks. Really, you have nothing to worry about, it will all be provided for you. Don’t worry when your friend shows up missing, they just went on a trip to a better place.

  18. Actually the FBI & CIA have had similar features on their land line phones & cell phones for years, I actually think It’s a pretty good idea & simple. You could take it a step further & do it to your laptop as well. I think a lot of people laugh & blow it off because they just don’t want to face the facts, Ignoring it wont make it go away. Although they can still track you with the GPS unless you take out the battery.

    The internet is being “listened” to constantly & signatures are applied to this traffic just check out the wiki on room 641A. We have seen many things from scifi movies become reality, Really why not 1984. Everyday more & more rights are taken away…

  19. I can’t believe how many people shrugged off the whole AT&T NSA secret rooms fiasco, You would think more people would care about that than gay rights, But you don’t see people marching in the street over this, It’s appalling!

  20. The machines are listening & learning, A.I. is getting smarter because of this, Soon there will be systems powerful enough to predict your actions. That’s still a ways off but it will happen. Quantum computers look for patterns, Such as in the recently released What does DHS know about you. From the gathered info they can predict future criminals, But what if the predictions are wrong? We can already determine the probability that someone will get cancer or any number of diseases & even deny them insurance based on that alone.

  21. Way too much paranoia! Set yourself a limit. And FYI, I can find more information about you over the internet than over the cell phone… BTW: I changed to xxxx the real numbers and other information and don’t want to extend this… the problem is not the government, is ourselves. Figure out Facebook for example how bad is that for our privacy. And we can continue… It is an interesting hack, but lame purpose.

    Domain Name:STAHLKE.ORG
    Created On:20-Dec-2008 23:05:15 UTC
    Last Updated On:12-Jul-2009 07:30:40 UTC
    Expiration Date:20-Dec-2009 23:05:15 UTC
    Sponsoring Registrar:Directi Internet Solutions Pvt. Ltd. d/b/a PublicDomainRegistry.com (R27-LROR)
    Registrant ID:DI_912xxxx
    Registrant Name:Daniel Sxxxx
    Registrant Organization:n/a
    Registrant Street1:5xx xxx Rd. Apt xxxx
    Registrant Street2:
    Registrant Street3:
    Registrant City:Fairbanks
    Registrant State/Province:AK
    Registrant Postal Code:99709
    Registrant Country:US
    Registrant Phone:+1.9077xxxxx
    Registrant Phone Ext.:
    Registrant FAX:
    Registrant FAX Ext.:
    Registrant Email:dxxxxxxx

    etc. etc. etc…

  22. shouldn’t it be possible to monitor any of the signals on any of chips to see if the phone is transmitting data to the government or whoever when it’s “off”? what about battery usage, wouldn’t that really create a much bigger power draw than when the phone was really off?

  23. @ will d.

    You could monitor the RF from the antenna with some test equipment, It’s not uncommon for phones to talk when they are turned off, I had an old nokia that would turn itself on sometimes & download a software update then reboot & that was in 1998. I believe most phones stay in an always listen low power recieve mode even when off, By that I mean It’s listening for instructions from the cell provider.

  24. Simpler would be to put phone in a sound-proof container when not using it. I would assume this also applies to BT devices.
    PERSONALLY? I want R/T voice encryption. But I suppose you’d have to be Busch or one of his cronies to be able to even get one.
    Gotta love the family plan though with the free text OH YEAH not

  25. To everyone whining this man’s too paranoid, go shove it. Yes the odds of any one person who is simply concerned of this happening being tapped this way are possibly small, it HAS HAPPENED.

    This is not sci-fi- it really has happened, on numerous occasions. Google is your friend.

    Whether we fear our government or not, it fears us. Constant public stories of erronious and illegal wiretapping are common knowledge. The “data center” room in San Francisco is real. Wiretapping innocents is matter of fact for the NSA, CIA, FBI, and DHS- and they will get away with it until people start doing something about it.

    The only difference between people calling this man crazy and the man who hacked this brilliant simple hack are AWARENESS and CONCERN. You don’t have to think you’re being targeted to care about this issue. It’s basic self defense.

    You don’t buy life insurance if you weren’t concerned something could happen to you, do you? You recognize the possibilities of bad things. This man shows his preventive measure with a hack.

    So what are you going to do? Sit there and not care? Screw healthcare, gay rights, 3 wars- this is what *I* care about- all those issues are important, but for people not to be marching against this in the streets while they do for unknown, uncompleted versions of healthcare reform? Sickening.

    As long as unchecked, ubiquitous survielance continues in America, WE HAVE NO CIVIL RIGHTS. Privacy is a RIGHT. Period. I need to move to a more technologically incompetent country that still has some infrastructure, like Canada.

    Finally- yes, he opened himself to scrutiny by publishing this. But someone’s gotta show others how and risk something. While you’re at it- make a reed switch to disconnect the battery somehow, until you need it- then no pesky triangulation tracking off towers.

  26. What the feds did in the past is update the target’s firmware and make it seem it was off while it was on and listening, but that required a remote firmware change, and it was on, just looked off.

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