hackaday lazy afternoons

Lazy Afternoons

ok this is totally unofficial and spur of the moment, but let me explain this tomfoolery.

since i started writing for hackaday and jason has become a father full time (congratulations so much by the way), it’s been a very interesting transition for me and i’m loving all you readers more and more. the tips and comments (good or bad) i truely appreciate and it shows that whether you love or hate the hack of the day, you’re here for good fun hacks.

so…we’re going to try this whole “lazy afternoons” thing. basically, you send in your hack, and during the afternoon, i check my gmail, see what’s up, find an interesting and (here’s the important part) easy to make hack, and post your hack up here for all hackaday readers to try out for themselves. not everyone can afford $600 for an android head, let alone know how to solder even sometimes. that’s ok. the important part is that you’re interested. so i present to you:

the world’s simplest FM radio jammer sent in by [megabite1]
FM Radio Jammer
we’ve all been there before. maybe we’ve even been guilty of it, but there will always be that person with the radio blasting unwanted music at a time that is not convienient for us. don’t get me wrong here, i don’t mind the occasional Run DMC “hard times” at 2am, but sometimes I need that sleep. so with a 100mhz crystal oscillator and a piece of wire acting as an antenna stuck in it, you can properly jam all 100mhz FM stations and apparently possibly the whole FM band. he says these are a bit hard to find, but dig around or try a place like mouser for one. either way, it’s good for some temporary relief when you need peace and quiet.

so until next time hackers, enjoy your lazy afternoon and keep sending in hacks. we love ‘em. no worries, hackaday links will return soon.


  1. Mike says:

    Nice. But who uses fm radio anymore?

  2. toxicbomber says:

    This could be a lot of fun waiting at a red light, while someone is blasting christian rock off their radio….DENIED!!

  3. Adam says:

    I saw this same mod on afrotechmods a while ago. http://www.afrotechmods.com/cheap/jammer/jammer.htm
    i hope he’s receiving due credit.

  4. Fat_Mike says:

    I was wodnering, what old device could happen to use a 100Mhz oscillators? Because I have ton and ton of old hardware that I use to salvage part for that kind of thing.


  5. battamer says:

    Thats the same URL linked to in the article.

  6. Brian detweiler says:

    Erm, Adam… Did ya _CLICK_ the link?

  7. sznik says:

    I’m gonna probably post my hack soon. Pretty easy to do, uses old keyboard (Linux for control – recommended;))

  8. deian says:

    As much as I like reading about the more expensive and difficult to complete hacks, this is a hack that I can work on without spending too much time, yet still have fun. I like the simple and doable hacks idea :-)

  9. awdark says:

    Can something similar be done with the AM band? I dont particularily like the chinese music my neighbors blair at 7am to 9am daily. -_- wish they would use headphones.

  10. Adam says:

    I’ve been having trouble finding a 100mhz crystal, anyone know where I can get one?
    (Btw, sorry either the link wasn’t working when I clicked it or I’m an idiot…)

  11. carpet says:
  12. carpet says:
  13. cde says:

    I don’t know about crystals much more then how to solder them when needed, but couldn’t you use the next closest above the range needed like you can for resisters or capacitors?

  14. JOHN says:

    Here too:


    It’s a cylinder oscillator, so I’m not sure if it’ll still work… If it does, it’s probably better for concealment in something nifty… Altoids Tin much?

  15. cde says:

    John, most crystals arn’t that big. If anything, you should be able to find one that you can fit with two cell batteries inside a relatively fat pen.

  16. John says:

    I like the “lazy afternoon” idea! This is a cool hack too!

  17. dewey says:

    So under this method would a 2.4 GHz oscillator disrupt 802.11 signals?

  18. CaptSnuffy says:

    i love the lazy afternoons hack idea!

  19. cde says:

    Dewey, and cordless phones, and cell phones, and microwaves (Maybe) etc.

  20. Matthew says:

    or an even better use would be a miniture cell phone jammer. IIRC, the newer systems use the 850 and 1900 MHz bands

  21. cde says:

    Ya should check Ladyada’s site http://www.ladyada.net for her Wave Bubble project. It blocks all radio frequencies.

  22. Captain says:

    how would this get powered? btw, I like the lazy afternoon idea too.

  23. ryan says:

    where? all i could find was the gamegrrrl that she made

  24. Will says:

    I love the lazy afternoon hack concept. Can’t wait to see more of them.

  25. Ginotech says:

    the oscillator he used from from a 90’s circuit board. will a brand new oscillator have the same effect of jamming all of FM? the ones im looking at are supposed to be very accurate and stable.

  26. francis says:

    I think this lazy afternoons thing is a great idea. I myself am a beginner in DIY and hardware hacking sort of things. I’ve been looking for a place to get start with easier projects, and this idea seems like it would help with that.

  27. Afroman says:

    Hi there
    To answer some of your questions,
    No you can’t use the next closest in the range like with Rs and Cs. Unless it is _really_ close like 98-102Mhz or something.
    You can power it with a simple 3.3V lithium (coin battery) cell.
    Yes the same principle can be used to jam 802.11x. However, you will never find a crystal that oscillates at 2.4Ghz so the project will be much more complicated.

  28. Enfusion says:

    Is it me or do there hacks look similar to make magazine’s blog? It migt be a good idea to cite your source unless of course u actually found the hacks by yourself through google or something. http://makezine.com/blog/

  29. Megabite1 says:

    I was thinking the same thing John. This would be an awesome hack for an altoid box. This one: http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=602085&e_categoryid=437&e_pcodeid=69507 looks good, but is anyone positive? I don’t want to buy the wrong part.

  30. Mattjr42 says:

    What do I do once I get this item. I have never done any hack before and i want to start to solder and make this hack. Could someone help me with other supplies i might need, Does this need a battery or somthing? How does it work?

  31. alkzy says:

    I havnt really ever replied but ive been here for awhile, i have to say I love hackaday and this crap is neat all of it, the jammer and ring are markable new ones, usb batter, infrared camera, hell more than i can name

  32. joe says:

    hey “enfusion” – check the make article, they link to afroman’s work. make cites afroman.

    check your sources tough guy.

  33. ladyada says:

    when i was reseaching jammers and related trouble-makin’ stuff i was refered to this nifty article that explains the theory behind ‘all channel FM transmitting”: http://www.tinaja.com/glib/muse91.pdf

    of course, extending the math to this situation: a 100.0000MHz crystal will indeed have a first harmonic at 100.0000MHz and therefore certainly jam any station transmitting at that frequency…but it would be really really weird for such a high precision crystal to have harmonics/variations that extend from 88 -> 108MHz. so, while i think its a very nifty hack, i’m curious as to whether/how it jams the entire broadcast band…

  34. pufuwozu says:


    Run DMC rocks. :)

  35. Boombox says:

    At ladyada.

    It could be the harmonic rich square wave put in the simple wire antenna somehow is distorted, making the band of noise wider. I also see no decoupling at all, so the wave coming out of it could very well be very distorted with not well defined edges (different harmonics).

    Well you could verify it by using the same setup, with decoupling and without. And then you check the output with a spectrum analyser. Not that i have such equipment lying at home, but at work we develop products that need to be compliant with CE EMC emissions, so i could make a small setup and measure it.

  36. barbobot says:

    Heh I can see the fists pounding into the steering wheel now.

  37. nick says:

    As someone said before, does anyone have any ideas what one of these would be used for in commercial products? (what could i possibly own that has a 100mhz crystal oscillator in it?)

  38. REX DART, ESKIMO SPY says:

    Can anybody confirm any of those purchase links?

  39. Neil says:

    This seems like a good beginner hack for me to try as my first hack. I too am wondering what commercial things have the 100mhz crystals in them.

  40. Neil says:

    This seems like a good beginner hack for me to try as my first hack. I too am wondering what commercial things have the 100mhz crystals in them.

  41. cde says:

    The Wave Bubble/Air Fresh project from LadyAda.net:


  42. Noggin says:

    You can probably find 100Mhz crystal in an old 486. Didn’t the DX2s or DX4s run at 100Mhz? They were pretty common at one time…

  43. jason says:

    Somewhere an FCC chairman is feeling a great disturbance in the force.

  44. Justin says:

    Would it be possible and relatively cheap to make a device that would jam 802.11 wireless signals? I would give so much to have one…when every teacher’s computer in my school runs on wireless…would make school about a billion times more fun. Please help!

  45. ending says:

    Well, apply the same concept but get a 2.4 Ghz oscillator and your set. Good luck finding one :P.

  46. ending says:

    Well, apply the same concept but get a 2.4 Ghz oscillator and your set. Good luck finding one :P.

  47. enfusion says:

    I dont know if u under stood me right joe, i was just saying if he got those hack ideas from make, then he should say that he got found out from make. I actually dont care but its sorta lame when u find 2 articles in a role the day after the make article was posted. If your gonna do that try to diperse it more.

  48. jondoe says:

    I am not an electronics guru by no means and was wondering if someone could confirm these two links validity for this “project”: http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=602085&e_categoryid=437&e_pcodeid=69507 & http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=118963 Thanks in advance

  49. William says:

    I think I found a 2.4 GHz op. Please goto the link below for a diagram (http://www.2sale.info/images/design.JPG) . Please let me know if this will work. Thanks

  50. William says:

    46. Posted Apr 27, 2005, 7:30 PM ET by jondoe

    I ordered from mouser, I will let you know this comes in and if it works

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