tomithy83

im gonna build a carputer for mp3's and i wanted to be able to pull it out of my car when parked for security reasons but i also wanted to be able to use it in the house so i planed on making docking stations in both my cars and my house. oh by the way the computer im gonna make is only gonna be as big as my car stereo. ive got all this planed out. then i got another idea. what about at work? ill have the car hence ill have the computer might as well be able to listen to my music at work. great idea aint it? theres a problem i work in a warehouse i cant just dock it nor can i walk around all night with a "car stereo" in my pocket. so i thought what about wireless headphones but i am low on funds and space. i cant spend much money so i'd like to make them but i dont know how. also i dont have much space i can spare more space on the transmitter than on the receiver lets say about 3"x4"x1" on the transmitter and thats kinda pushing it. on the receiver id like it to be as small as one of those tiny mp3 players i am not real woried about sound quality as my work is loud anyway so more than likly i wouldnt be able to tell much of a diference. if posible id like to be able to "dock" the headphone unit in the computer when im done to charge the batteries but this isnt a necesity. also if posible id like to be able to have 2 or 3 or more sets of head phones so i can loan them out to the guys im working with

i thought of acouple ideas on how to acomplish all this but i dont know if any will work : i could use a cordless phone,walkie talkies, i know there are also fm transmitters but ive heard ALOT of bad things about them let me know if you have any good exp with them

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Spaghetti

You might as well just get an ipod or Creative Jukebox - easily carried on the person whilst on shift.
As for the transmitting, you could go for the walkie talkies and wire up a set of pmr radio's (FRS if you're in the states). Those little radio's are pretty good quality transmission-wise and work well in built up areas, but I think continuously transmitting music is illegal as far as I know

tomithy83

well i, as many here, dont care about those types of legalities. where do you think i got most of my mp3's to begin with you think i got them legaly?

and i like to do things myself makes me feel good knowing i made it. even if i spend twice as much to make a mp3 player that is 3 times as big as an ipod that only holds half as much music and is of a poorer quality plus i'll have bragging rights "you made that?" "yes i did"

not to mention iev already spent moe than i should have on the carputer might as well get that much more use out of it

EBFoxbat

I think transmitting of FRS is not so much legal. But if it were to be a private walkie-talkie system, then you can't legally listen in so anyone who catches you has to break the law to do it.

Potential problems:
1) Your warehouse probabaly isn't conducive to wireless transmissions.
2) You can't change songs at will.
3) How are you going to power the carputer w/o draining the car batter.


I wish I didn't have that problem too. I'd save alot of money and have a better product You might want to bite the bullet on this one. I have this 30 GB MP3 player ($240). I love it. 17 hour battery life, rechargeable battery. Excelent quality. Plus I use it to carry files from my desktop to my carputer (as USB 2.0 is alot faster than 11mbps LAN) It can play MP3s, WMAs, and WAVs, but can carry any type of data.

You might want to consider an FM modulator. Plug it into an MP3 plater and put it in your pocket. Then pick up some FM headphones (you wear some and give them to buddies) and all tune into the frequency that your *** is broadcasting at. My FM transmitter

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Jailer

I think in order to have a "Private" 2 way radio system you need an FCC License. Be aware though that anyone with a scanner will be able to pick up your signal. Something else you may want to consider if you are considering transmitting over FRS is that even if you don't care about the legalities of it someone else using it in the area may and could very well report it to the FCC. I wonder if the FCC or anyone else for that matter would consider that a pirate radio station.

EBFoxbat

I would assume you need special licenses from the music producers to braodcast it, like radio stations do.

You cannot broadcast to the masses w/o the record company's permission. (I'm thinking big fine, jail time.)

Plus the FCC strongly dislikes spamming FRS frequencies because they are very heavilly used in some areas. Broadcasting continuously renders that frequency useless. HAM people can be anal (sorry if anyone is a HAMer). I wouldn't be surprised if you get a phonecall.

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tomithy83

i did a bit of looking and frs is notan option it is illegal for one (dont care)but like you said anyone could call fcc. i dont mind bending the law but i dont really wanna chalange the government to come get me


i really like the idea of an FM transmitter but i have hearn a lot of bad things about these like the FM band is so cluttered that finding a clear station is hard to do. ive also head that quality sux this isnt a big issue with me but i would atleast like to be able to hear the music fairlyclear please let me know if these issues are unfounded


1) i may have issueswith the wireless transmissions therebut there will be nothing i can do about that *hope*&*pray*
2) i have winamp startup my last playlist where it stoped when windows restarts plus i have several play lists set to buttons on the outside of the computer so wheneve i feel like a change i can walk over andpress a button to change playlists plus i have winamp startup my last playlist where it stoped when windows restarts. ALSO i will have a ifared port on the comp and a tiny remote so changing songs isnt an issue
3) my carputer is going o be dockable when i leave home i'll pull it out of the docking station in my computer desk walk to my car slide it into the docking station in either one of my cars listen to the same musis in my car as i was just listening in my house when i get to work i'll undock the comp carry itintowork plug in a power cord that converts 110vac to 8-30vdc as my power supply runs on 8-32 volts

EBFoxbat

The one I have lets you select the frequency to broadcast on. It's has a digital LCD readout. I always use 88.1 in my car because thats not a used frequency around here. The quality, in my opinion, is exactly the same as radio, which is fine.

A problem for you, is that it only broadcasts (with acceptable reception) for about a 30/35 foot radius. You might ask the smart people on here to helop modify the transmitter for more power (also illigal but much harder to catch and will **** much less people off)

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crisr

C'mon, guys... FRS? You can't be serious... all the legal and ethical issues put aside, these things are designed for voice transmition, they have a very limited frequency response (around 300-5000Hz) and very low dynamic range (high compression). Have you tried listening to music through them? It's worse than through the phone (think of PBX on-hold music).

For what you are trying to acomplish, without a portable music player, I think 2 of the options are: Buying / building an FM transmitter (I think you can find schematics on the net) and using an FM headphone or buying 900MHz wireless headphones - from US$40 to about US$80. These two options are specifically designed for music. You will end up spending anyway, whether building the FM transmitter and buying the FM headphones, buying the 900Mhz set or even a pair of FRS walkies + headphone, so I recommend the 900MHz headphones.

tomithy83

i beleive im going to buy a pair of 900mhz headphones and mod them to fit my needs:

removing everything but the circut boards
add one of those little ear bud speakers
make/find a case for the circut boards

any sugestions very welcomes

SebQc

tomithy83: This is a little bit out of subject but i will like to know more about your docking station project because i'm also planning to do one. What kind of carputer do you have? C134? Iwill ZPC?

I have to find a solution for winter (i'm from montreal) and for thiefs...

NiN^_^NiN

Well you might as well use a FM transmitter then get thoese small $10 digital radio's

U can get a FM transmitter very cheap and it will transmit 300meters if thats enough.



grab a small radio like that

then buy the ransmitter



That uses a two transistor two stage transmitter which makes sure the radio doesnt drift and outputs clear sound

mind u im in australia and these are australian things but there will be up there

and thats very cheap it cost $50 all up also cause its FM only u would pick up the reception in the warehouse plus if anyone does scan and find the music its FM they wont be thinking illegal

so good luck

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