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diy wireless transmitter?

Discussion in 'Pickups & Electronics [BG]' started by knexfreak32, Dec 14, 2013.

  1. I want to make a wireless "cord" but i need schiematics please help
  2. Selta


    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    Not a simple task, really... you're much better off buying a proven system from someone like Line 6. But, in the interest of actually trying to help... what is your design goal, and why wouldn't something currently on the market meet that? What do you know about electronics and digital data transmission?
  3. Bassamatic

    Bassamatic keepin' the beat since the 60's Supporting Member

    Very Very Very Difficult. Even if you could get a schematic and parts list, the specialized parts will be hard to get and the manufacturing technology, PCB layout and shielding are very critical for wireless audio products. In addition, wireless instrument units require very large dynamic range, and low noise and low distortion. Not easy to do. Even the very early Nady stuff from 25 years ago was fairly high tech - not easy to make even then.

    Just buy some older used gear with your money.
  4. Even harder than making one that works well for yourself is making one that does not cause any interference with other wireless systems around you.
  5. All you had to do was google it. There are schematics everywhere... BUT:

    1. You have to transmit in legal bands. Some frequencies are illegal. Stay FAR, FAR AWAY from those.
    2. Most legal frequencies are used already. This means interference. Can you imagine being in a show and hearing a hobbyist voice from next door through your amp?
    3. You can buy a perfectly funtioning, already built wireless guitar/bass system commercialy for less than 100$. Seriously. Not worth it.

    EDIT: I see your name is knexfreak. I can only assume you aren't very old (your spelling/grammar skills don't help), making a project like this even less likely to happen. You won't find transmitter and receiver parts at Radioshack. You have to order online.

    After all this, if you still want to build one... I can link some diagrams.
  6. I was just thinking of a simple crystal ocilator and a am radio connected to my diy speaker system in my room. not hifi but good for practice. Not looking for gig/concert grade.
  7. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    It might work, but will definitely not be hifi. In particular you will lose all bass frequencies. I built one of the DIY wireless once. Worked ok on guitar, didn't work at all on bass.
  8. Crater


    Oct 12, 2011
    Dallas, TX area
    There's a bit of legal leeway that allows for "experimenters" build build very low powered radio transmitters, probably of a 100 milliwatts or less, and only on certain bands/frequencies. Read up on the FCC's (federal communications commission) "Part 15" rules. Otherwise, only LICENSED amateur radio operators ("Ham radio") can build and operate radio transmitters, and only within the well-defined frequency bands and power limitations.

    There are numerous experimenter transmitter kits, most use the AM or FM radio broadcast frequencies, your best bet is to adapt one of those.
  9. mrbell321


    Mar 26, 2012
    N. Colorado
    TI(and very likely others) has reference circuits using their hardware for this sort of thing, but they're not simple AM circuits. AM circuits are nearly doable too, but will probably be of relatively low quality. It would be a fun thing to expirament with. Just google around for beginner AM transmitter and you're sure to find something.
    I wouldn't worry too much about the FCC. As long as you're staying low power(and you surely are) and you don't try to sell these things, there's really no reason for them to come after you. If they did it would likely be a "don't do that".
  10. I've dabbled into the wireless thing, but let me tell you what, it is a p-i-t-a to make a stable rf oscillator that can transmit more than five feet, and that doesn't require a precisely tuned antenna. Plus, you have to figure how to make the sound have minimal distortion. I personally find it easier to make a pitchshifter out of bbd chips than to make a wireless transmitter. If you can pull it off, though, then be sure to post some schematics...
  11. RobbieK


    Jun 14, 2003
    For home use, and for fun and education this is a great idea, but as others have said, not really an option for gigs. There's lots of kits for fm bugs around that I'm sure you could modify to plug a bass into. They generally have an electret condenser mic at the front end, so you'd have to put a little buffer preamp in there instead with a fet or something. I made a few of these as a kid, and managed to plug my guitar into them a few times to hear myself out of my dad's stereo!...
  12. Not a bad idea! I could slap a transformer where the condensor mic is... food for thought....:what:
  13. BbbyBld


    Oct 13, 2005
    Meridian, MS
    If you want to build one just to do it for fun, the easiest way to build a FM transmitter that I know of is to build a colpitts oscillator with a single transistor. For the standard FM broadcast band, a 2N2222 transistor works very well. All the parts are easy to come by and are cheap except for the coil. You'll have to make that and tune it, and it usually takes several attempts. That's the PITA part friedtransistor is probably referring to. You inject audio at a certain point in the oscillator, which modulates the frequency and broadcasts very effectively. You can get about 100 yards of range out of it and it sounds as good as an FM radio station broadcast. It's illegal, but you won't be broadcasting with enough power to cause problems, but be aware.

    It's difficult to build a usable transmitter (even from some kits) without test equipment like an oscilloscope and spectrum analyzer. Even if a kit works, it may be working right above or below a broadcast band and will probably need coil tuning.

    Get an amateur radio license. It's very easy these days. You can then make a transmitter and receiver and keep it legal.
  14. derg

    derg Supporting Member

    May 26, 2005
    Cleveland, OH
    years ago i converted a mr. microphone into a wireless transmitter - this would have been 1980 or so.
  15. Anyone know how much licenses are
  16. Nothing.

    No, really! The exam costs $15, but the license costs nothing and is good for 10 years.
  17. Really? And what does the exam consist of? Also, what surprises me more is you are in California. I would have thought it would be impossible to get a license down there, with all the laws and stuff.
  18. Yeeeeeeees. And I'm pretty sure you never get to eat anything but corn, right?

    The exam consists of . . . questions.
  19. Ha, I was sure you'd say something about beef instead, but I get your point.

    Ok, so the exam is $15, they ask you a few questions, hand you a license, and that's it? Seems too easy...
  20. Crater


    Oct 12, 2011
    Dallas, TX area
    Yes, but they're technical questions, not "What's your mother's name?" and "What's your favorite color?"

    This won't help you though, any and all music is prohibited on ham radio, period. Speech only. You are not even allow to sing "happy birthday" to a friend.

    Again, find an experimenter's transmitter kit, they are only about $30, and it will be much more likely to work at first than something you build yourself. The power and range of these is low, but should work for your purposes. And it will be perfectly legal as long as you don't modify the circuit.