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The proceed with caution warning is there because it is actually illegal to jam a cellphone signal in the United States... they're just trying to protect themselves.

i meant proceed with caution as in i have no idea if you can order one of them (or should, all depends on where you live, local laws, etc etc etc disclaimer)....

This would be perfect for bringing to the movies. I may have my next Make project!

It's so nice to finally see these come down in price. Tuning is tricky though without a spec an or counter and there are six variable capacitors to mess with there... Maybe get some friends to lend you their phones to test.

Scary how mad some people will get about this stuff though...

"...i have no idea if you can order one of them (or should, all depends on where you live, local laws, etc etc etc disclaimer)...."
wouldn't it be great if all legal disclaimers were this short? Is this an official O'Reilly disclaimer? :)

No seriously... THINK for a second why these are illegal. (They are illegal on a Federal level not "state and local" laws).
Here's just two that I thought of off the top of my head...
1) I'm in the mall, and one of my fellow makers has one of these gadgets in his backpack near me. Turns out, one of my family members was involved in a serious accident and is trying to get a hold of me. Now think if it were one of your family members or friends and the tables were turned? Who would you be more mad at, the maker who built this cause he thought it would be funny, or the magazine that taught people how to do it - or both?

2) A group of bank robbers get a hold of one of these devices... They burst into the bank, and hold all of the patrons as hostages. One of those hostages is YOU. But then you get a moments break to grab your cell phone and call for help... But no... Because one of the bank robbers learned about this device on the makezine blog.

Do unto others as you would have others do unto you.

I know, I know... these plans are on the intertubes. Anyone can find them... But should illegal plans be found on "my" beloved makezine pages? One lawsuit could abolish this magazine, and I don't want to see it go. That's why I feel passionate about this.
If your gonna post questionable material at least cover yourself with a REAL legal disclaimer.

cyenobite - this isn't the pages of MAKE, it's the blog... we're writing about a project *someone* else did on instructables - we write about things that are happening, there's a lot of debate about these devices. churches and movie theaters want them, but others think that wouldn't be fair if some orgs could have them and individuals could not... people are making rf jammers, people are modding them, we write about these things.

1. this "mod" likely doesn't work. getting cell phone coverage in a mall usually doesn't work out that well either :) a low powered jammer wouldn't stop someone from making a call a few feet away.

2. bank robbers using a low power device would not get very far. the alarm systems are not wireless either. again, a device like this doesn't work more than a few feet, at the most, if it works at all. if jamming cell phones were the key to robbing banks why hasn't this happened before?

there isn't a need for a legal disclaimer we are *linking* to projects that are out there, you might want to email the people who created them and/or post up in their comment sections too.

either way, keep chattin' here - all opinions are welcome, this is interesting stuff.

Seriously folks. Forget illegal. This is major antisocial, irresponsible behavior.

If someone's annoying you with a loud cell phone call, speak up and ask them to be quiet. They're the rude one, not you. If you just don't like that they are using a cell phone and you've just GOT to MAKE them stop... get some professional help.

Jamming the radio waves that people have come to accept as available in times of emergency, simply in the name of teaching someone who is annoying you a lesson, will make you a contemptible, selfish coward.

This is nothing like the TV-be-gones. Turning off someone's TV is a practical joke. Running these devices is an attempt to steal someone's ability to communicate. We're talking serious civil liberty issues. Again, forget illegal (though it is thoroughly so). I'm talking malicious and wrong.

Regarding your points 1 and 2... saying that it's unlikely to be successful is NEVER an excuse to attempt something harmful. And it should be obvious to you that by adding an amplifier stage or a better antenna, ANY low-power jammer can be made more potent. Suitible amplifiers are readily available in amateur radio circles.

Regarding the fact that theaters and churches want these... it's equally reprehensible for them to want the right to use these jammers, and it should continue to be illegal for them to operate them.

Phil, I love your blog and I don't in any way intend to malign your sense of right and wrong, but I suggest you reconsider your opinion on this, because I don't think you've thought it through completely.

I agree that you can't undiscover information or make ideas go away, and that you shouldn't try. In fact I think it's wrong that even LISTENING to certain frequencies is illegal in the US. But it's absolutely proper that jamming them is illegal.

But as someone in a position to make 'cool projects' popular, I think you have a responsibility to consider what you associate yourself with and what you present to others. You do have the ability to refrain from helping make popular something this ugly.

What I love about Make is that the projects are creative and constructive. They're about contributing. This project is about trying to take something substantial away from someone else, namely their ability to use a cell phone. It's wrong, and I think it's out of place in the Make community.

drg72 - i don't think i commented about this being right or wrong, only that someone is doing this, companies are selling these devices, people are modding them. it's very interesting that these devices exist, they're being sold and someone is modding them.

why do people want these? why are cell phones so useful but annoying all at the same time for some? all good things to discuss.

the comments are here for others to debate about how the right-wrong-ness, i don't have an opinion about this yet.

I thought of letting your responses go, but I'm going to respond back. Don't worry, I won't keep nitpicking this, and you know I respect your opinions as well Phil. I won't respond after this :)

"This isn't the pages of MAKE, it's the blog" -
Is the blog any less important than the printed page? Not sure why you pointed this obvious point out.

"writing about a project someone else did" -
In addition to that, you provided a link to a store to order these things. That's not an educational link. Some may even say that would be considered an advertisement.

you poked holes in my two examples from a technical standpoint... But didn't respond to my moral point - ie: Would you want someone to block your cell phone?

You got me on the "linking" to projects as far as a legal disclaimer. I still think it's wrong, but obviously we disagree there.

You suggest I post comments on these other websites... To be honest, I don't care about those other websites. IF someone should sue them for selling a device that is illegal to use then so be it. I DO care about MAKE. I also posted here, because you encouraged debate on this post. (I think you threw that in just for me, as you probably remember I've commented on previous posts of yours that skate the edge of moral responsibility - imho - ie: the matchstick bomb, how to break a bottle with your bare hands, etc...)

Thanks for getting my brain working today. I appreciate all your posts (even the ones I disagree with).

>>I thought of letting your responses go, but I'm going to respond back. Don't worry, I won't keep nitpicking this, and you know I respect your opinions as well Phil. I won't respond after this :)

naw, please do - this is why i post things like this - we're all discussing things nicely even if we don't agree. most sites can't do this, but we can!

>>Is the blog any less important than the printed page? Not sure why you pointed this obvious point out.

not less important *but* very different - part of this post is the comments and discussion, if this were print it would be one-way. this post can be updated, edited, debated - heck we could get told to take it down. so i don't consider it like the magazine at all and it's why make print and make online work so well together.

>>In addition to that, you provided a link to a store to order these things. That's not an educational link. Some may even say that would be considered an advertisement.

we don't get paid for linking to that store, i'm not even sure if the store will send you anything at all. but i did want to include all the information i could find, including the link.

>>you poked holes in my two examples from a technical standpoint... But didn't respond to my moral point - ie: Would you want someone to block your cell phone?

that's a good question. it would all depend on so many things. it's almost like saying would i want someone to be able to slow my car down remotely. maybe, maybe i was driving dangerously and should be stopped.

one thing i'll say, cell phones have always let me down. i rarely rely on them, coverage is awful, batteries die - i think they give some people a false sense of security.

>>You got me on the "linking" to projects as far as a legal disclaimer. I still think it's wrong, but obviously we disagree there.

we're just covering what's going on, i think if ignored it or gave some strong opinion and omitted links, that wouldn't be good either.

>>You suggest I post comments on these other websites... To be honest, I don't care about those other websites. IF someone should sue them for selling a device that is illegal to use then so be it. I DO care about MAKE. I also posted here, because you encouraged debate on this post. (I think you threw that in just for me, as you probably remember I've commented on previous posts of yours that skate the edge of moral responsibility - imho - ie: the matchstick bomb, how to break a bottle with your bare hands, etc...)

Thanks for getting my brain working today. I appreciate all your posts (even the ones I disagree with).

no problem, keep on reading and discussing - it's why i posted it up. diy projects usually don't have social, artistic and legal issues - this is good stuff.

So some are suggesting that during an "emergency" someone is going to be following others around, blocking their cell signals in a cowardly electronic manner? Seriously? I mean, let's think through the practical realities of using something like this. I've seen units that were claimed to block signals for up to 90 feet but they were large, for fixed installations, so we can assume that the antisocial cowards prowling the streets after emergencies won't have them, and those smart enough to boost the range of the portables will probably be smart enough to be dealing with the hypothetical emergency instead of stealing people's right to communicate.

The hooligans will have jammers with much shorter range. As someone loses their cell signal (or it's jammed), they will likely move in a clever ploy to steal back their ability to communicate. To keep blocking, one must follow them fairly closely (and not get bored, this part is key). That would look very odd, and attract the attention of the person whose right to communicate was being stolen, and since the blocker is a coward this is the part when they get beaten up. All's well that ends well!

And I wonder why other countries allow these to be sold? Do they see the threat as somehow less dire? The development of things like this is an inevitable consequence of the dynamic tension between those advocating the right to talk anytime, anywhere and those advocating the right to occasional peace and quiet, like say in the MOVIES or CHURCH or a hotel room with a new special friend. And being jammed in a theater is far preferable, I would think, than what I had to do before the jammers came along: 20 ounces of Coke, ice and all, on their head. I tried diplomacy first, but it proved ineffective (OK, I'll admit that only happened once, when it all came together perfectly).

Besides, the very best cellphone jammer is a hurricane. Or an earthquake. And sometimes a flood. Blizzards, too. And the solar maximum in 2010 will play havoc as well, as it's predicted to be unprecedented. Cell phones are really only useful for localized, personal emergencies (or extreme, improbable fantasy hostage scenarios and what-not). Having faith that they'll work during anything large-scale is sure to be, um, disappointing.

So jam on, ye seekers of quietude!

drg72 wrote:

"This is nothing like the TV-be-gones. Turning off someone's TV is a practical joke. Running these devices is an attempt to steal someone's ability to communicate. We're talking serious civil liberty issues. Again, forget illegal (though it is thoroughly so). I'm talking malicious and wrong."

and:

"Regarding the fact that theaters and churches want these... it's equally reprehensible for them to want the right to use these jammers, and it should continue to be illegal for them to operate them."

If I don't own a cell phone and go to a movie theatre that uses a cell phone jammer, will anything be stolen from me or will I have and civil liberties taken away?
How does owning a cell phone grant you *more* civil liberties (for lack of a better term)? Why do you think that owning a particular piece of hardware grants you a right to use it everywhere on public or private property?

What if the use of your hardware interferes with what I do on my private property? or on the private property of a third party which we both occupy (eg movie theatre)?

I'm struggling to get the point out clearly so I'll fall back on bad analogy. Does owning a car mean you have more liberties/rights/freedoms than say a cyclist or pedestrian? I guess don't confuse access to a technology with an increase in liberties/rights/freedoms - otherwise rich people would end up with more rights than poor people.

My enjoyment of going to a movie theatre has diminished in recent years as the uptake of cell phones has increased. I don't want to have my paid for experience interrupted by anothers rudeness/forgetfulness. Can I demand my money back from the cinema if some threshold level of cell phone disturbance disrupts the experience for me? Can I demand compensation from the idiot who used their phone? Not likely.

The emergency situation is an interesting one. It is hard to argue against allowing cell signal to allow for emergency situations. However for decades people went to the movies without cell phones and probably with little loss of life as a result....

I own a cell phone. I still go to the movies. I make sure I switch it off when I go. Do I think jammers should be installed in movie theatres or churches....no I don't.

I would like to see the telcos and phone industries resolve the problem by providing theatres/schools/churches etc with "cell silencer" that forces the phone to silent mode rather than complete signal cut off. If the phone doesn't ring/beep people won't be as tempted to answer it to quieten it (which they often follow up by actually having a conversation - idiots). Outgoing calls would still be possible, but hopefully enough politeness remains that people would walk outside before making a non-emergency call.

Hello all,

I like pookyofdoom's idea of a "cell silencer" - though I would suggest it also sets the phone on vibrate. The trouble is with all the different phone types out there getting one device to talk to all of them. That would be an interesting project! I can't think of a way into a non-bluetooth phone that doesn't require the cooperation of the original phone vendors or exploiting some sort of buffer overflow in the code or similar.

As for the jammer itself, I'm of the opinion that people who need connectivity will notice the poor reception. For theaters and churches, a non-illegal way to accomplish the desired "no cell service in this area" is to make the place into a Faraday cage, appropriately constructed to block cell signals. There will be holes at the doors, but minimal. Then post signs saying "This area has very poor cellphone reception. If you are expecting an important call please contact the manager and give him your seat number so that an usher can come get you when the call comes in." Why jam when you can block?

My own personal prank-desire is to have a short-range omni-frequency transmitter so I can talk to the driver who just cut me off on the road through their stereo, regardless of whether they are on FM or AM. A spark-gap transmitter will effectively intefere with their reception quite well, but I don't know of a way to get sound output that is recognizeable regardless of frequency setting. It's also rather omni-directional, and I want very targeted with no bleedover and a limited range.

As others have posted, using a cell jammer would effectively put yourself in possible legal jeopardy, if not physical jeopardy, depending on what you are doing and where. Same with my transmitter thing, I would guess. As for how to deal with rude theatergoers/churchgoers who have conversations? (heck, had to sit through a phone conversation at a wedding once!) the trouble is, any physical contact you make on the person is assault. One's only recourse to a rude one who doesn't respond to polite requests is to alert the ushers (if any) and have the guy kicked out. Unless you want to risk assault charges...

Be safe,
-cajun

A very interesting discussion. Here's another view.

I'm a high school teacher. We have a rule against cell phone pocession (but it isn't enforced). I enforce what I can in class but you have to actually catch them in the act. I would love a way to render their phones useless while they're in the classroom. Well, I can dream.

On an invitation from friends, my better-half and I drove from Dallas to attend the Shreveport Opera's recent production of "Sweeney Todd, The Demon Butcher of Fleet Street." During a strategic moment an audience member's phone rang. This was well after a polite gentleman on stage introduced the production and asked that no photos be taken and for everyone to turn off their cell phones or put them on vibrate.

The guy who's phone rang ANSWERED HIS PHONE and began an extended "stage-whisper" into it, apparently involving some schedule for picking up members of a girls soccer team the following day.

In about two minutes the audience directly around the miscreant almost lynched him. Finally demanding LOUDLY that he end the call or leave the theatre for the lobby. He finally snapped his phone shut angrily and glared at everybody, uncaring that he was being so rude to about a thousand people, including the performers.

That is just one of the reasons why I think jammers are such great things. I plan to order one today, illegal or not. Rules are made to be broken.

Screw the rules and all you goody teacher's pet little dancing pussies!!!! I have one of these and it's the best money I have spent on any electronic device....period!! If you wanna yap your gaping hole off on the phone in a public place then be prepared to have the plug pulled on you. I nail several rude offenders on a daily basis. What out, cause you will be next!

Looking for a cell phone interupter that will work like a garage door opener? Something that will disrupt just long enough to hang someone up. Say the car in front of me when they are talking on the phone and not paying attention to how they are driving.

Looking for a cell phone interupter that will work like a garage door opener? Something that will disrupt just long enough to hang someone up. Say the car in front of me when they are talking on the phone and not paying attention to how they are driving.

please i need to know where to by an intelligent cellular disablers

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