Broadcasting computer audio to FM radio channel. Where to find one?

[unclet]

I current have something which connects to the mini RCA sound jack on the back of my computer and then broadcasts the audio sound to a particular FM channel (ie: 89.2, etc..).  As a result, when I tune my FM dial to this channel, then I can hear the audio from my computer.

Thing is, this little hardware thing I have is battery operated and I would like to replace it with something which can be plugged in all the time since the batteries drain quickly.

I am not sure what these things are called or where to look to find one which does not use batteries.

Any ideas would be appreciated.

[HaRuMaN]

Why not just take an adapter that outputs the correct voltage (usually 1.5V or 3V) and connect it into where the batteries go?

[unclet]

I was hoping this might be an option, but I have no idea where to solder the wires to make it work.   I do have various spare adapters so I believe I can find a suitable one to use. 

Currently the little hardware thing I have uses two AAA batteries (positioned side by side to each other) for power.   Will you please explain where the wires should go?

[HaRuMaN]

Typically, in a side by side arrangement, one end will be connected ( a solid piece of metal that touches both batteries ) and the other end will have two separate contacts.  You'll want to solder to the end that has separate contacts.  Solder positive to positive, and negative to negative, and you should be fine.  If you can't figure out which end is which, post a pic and I'll point you in the right direction.

[DrumAnBass]

I never had much luck with the cheapo FM transmitters. I was always tempted to buy one of these: http://tinyurl.com/yteco8

[HaRuMaN]

Well considering that's like 10 times the cost of an el-cheapo...

[knave]

If you do try to hack in a power supply make sure you test the voltage. Many of the wall warts run high without load so a 3V PS could run at 6V or higher.  If you find one that is regulated this should be ok.  I think some cell phone chargers run at 2.8 or 3V those should work.  Hmmm...I wonder if you could take some of the 5V from a USB port? Any way to cut this in half?

[BobA]

3 diodes in series with the 5v will cut the voltage down to 3 v.  The diodes have to be able to carry the load of the unit being powered so 1n4001 to 1n4004s work well as they can carry 1 amp.

+5V supply    >|  >|  >|   unit being powered   Gnd or Return

                      0.7 0.7 0.7        2.9V

[MinerAl]

Find one of the el-cheapo ones that plug into the car cigarette lighter.  It should be really easy to get 12V (either from your PC or a wall-wart) to run it.

[EwJ]

This piqued my interest so i did a quick search.  Found there are some usb-powered fm transmitters out there.  The following are not really 'el-cheapo' though (range from $30 to $90).
Don't know if this helps - just throwin it out there.
As already posted, it would be a cheap hack to a wall adaptor or usb plug or something for what you already have.  New toys are fun though.

LineX

nexxtech
Relatively cheap.  Read the reviews - sounds pretty good.


wholehouse

sww
This SoundWithoutWires one sounds ok for the cash.  See this old info before ordering direct though:
sww_mp3car

[unclet]

Ok, thanks for the information ..... I might just try to hack my current battery-operated unit.  I will try to post a picture of it soon and perhaps someone can tell me exactly where the wires should b soldered.   I have to dig out some adapters as well to see what kinds I have stored.

[HaRuMaN]

Ok, thanks for the information ..... I might just try to hack my current battery-operated unit.  I will try to post a picture of it soon and perhaps someone can tell me exactly where the wires should b soldered.   I have to dig out some adapters as well to see what kinds I have stored.

I've always suspected that a couple of parts could be altered and the power of those cheapo transmitters increased substantially.

You wouldn't need more than a watt or two to blanket a house...

Yeah, I've thought the same...  I've got a couple laying around, I may have to play with them.  It'd be great to listen to Pandora over the home theater system.

[Namco]

I've seen kits (basically a schematic and a bag of parts) at the local electronics store) for around $40. It's a bit pricey, but the customizability of such a device would be awesome.


.... aah, here it is: http://shop1.outpost.com/product/1742989;jsessionid=PyKcz6zkM-hXZ+BGtdLl5g**.node3?site=sr:SEARCH:MAIN_RSLT_PG

The picture looks a lot like the one on Ramsey's site, but what you actually get is a bag or parts, instructions, and no fancy black box.

[unclet]

My house has a speaker intercom/radio system installed in each room as well as in the kitchen/family room and outside patio area.   All I have to do is tune to channel 89.4 on the main panel (located in the family room) to hear the music from my computer all over the house.   Works great, except the FM transmitter I use currently runs off of batteries. 

When I get time, I will post some pictures of it and someone can help me figure out what kind of power adapter (voltage/amp) to use as well as how to solder the wires.    I do not want to ruin my computer of course ...... and I am electrically challenged, so figuring this stuff out for myself is just not going to work.   Although I can solder and have a voltmeter   

[tba]

just get one of these:

http://www.dealextreme.com/details.dx/sku.3102

less then $10 shipped  and it plugs right into a USB port on your computer, i have one for my car and it works great... it shows it with a car 12v adapter, but that is just a 12v to USB plug converter.

[unclet]

Pictures of my current device as well as some adapters I have available are attached below.   Perhaps someone can tell me exactly how to determine which wires of the adapter is negative/positive and then how to connect those wires to the FM device.

tba
Are you saying it comes with a USB cable which can plug directly into my computer and I would not need to use batteries at all?  Or does it just come with a wire which connects from the car cigarette adapter to the USB adapter on the device?

[tba]

it comes with a micro USB to USB cable that plugs directly into a USB port for power and doesn't need batteries.

it also has a 12V to USB plug adapter for use in a car OR you can run it on batteries but they only last about 5-10 hours.

[unclet]

tba
One more question .... lets say you set the FM channel to 102.0 and then turn off the computer, then when you turn the computer back on does it still remember it is on FM channel 102.0 or does it reset itself to some other default channel?

[tba]

oooooo, good question.

I am not sure, and my G/F has the car with mine in it... i will check when she gets home and post the answer.

If you use a powered hub you could get around it, assuming you didn't unpower your hub, it would just stay powered at all times.

update: OK, i just tried plugging mine into the front USB port on my computer and the transmitter stayed power on even after shutting down my computer.  so it stays on channel even after power down and reboot.

at least it does on mine, your experience may vary.

[unclet]

Thanks for the test results .... 

I might have a try at hacking my existing one, but if it does not work out then I might just get one of those your recommended.

If someone could please give me some direction on how to connect the wires that would be great.

[heffe2001]

just get one of these:

http://www.dealextreme.com/details.dx/sku.3102

less then $10 shipped  and it plugs right into a USB port on your computer, i have one for my car and it works great... it shows it with a car 12v adapter, but that is just a 12v to USB plug converter.

That looks almost EXACTLY like my Belkin Tunecast2, except for the 4 buttons along the bottom.  Mine doesn't have a USB port on it either tho (but does have the power hookup, 12v, 200ma).  It DEFINITELY sucks down batteries, but it works great in my van.  Never thought about using it for music in the house though...

[ratzz]

You know, this would be a great way of using this technology for a wireless 3d surround sound -- albeit with a radio plugged in behind you ... Hmmm, I think I will look into this! 

[RandyT]

FM transmitters usually suck, with a capital "uck", but may be ok if you don't have a lot of traffic on the dial in your area.

Tell me, do you have a means of plugging in an external input to your sound system?  If so, you can sometimes find inexpensive 2.4ghz transmitter receiver combos which have pretty decent stereo audio capabilities.  At one point, I used one on my setup to get audio from the computer to the stereo and it worked quite well.  And, they just plug into the wall.

RandyT

[psychotech]

Well..

just get one of these:

http://www.dealextreme.com/details.dx/sku.3102

less then $10 shipped  and it plugs right into a USB port on your computer, i have one for my car and it works great... it shows it with a car 12v adapter, but that is just a 12v to USB plug converter.

Yes, as tba said, get one of these!

It's exactly what I'm using on my jukebox ..in addition to the inbuilt speakers and two independent RCA stereo outputs etc.



USB powered etc. and works actually quite nicely considering its price ..

 

[unclet]

Ok, I just bought one ..... it even came with free shipping .......   

[EwJ]

Perhaps someone can tell me exactly how to determine which wires of the adapter is negative/positive and then how to connect those wires to the FM device.

If you look at the diagrams on the back of the adaptors - they show centre 'pin' as positive, the 'shield' or surround as negative.

Are there any other provisions for power on that device besides the batteries (car adaptor or any other adaptor socket)?  If not,  the only way to connect might be to the plates for battery contact.  You would be looking for an adaptor with approx. 3v output.  Some cell phone adaptors are in this range.  The ones in your pics are too high - don't know if the 5v Zip adaptor could be modified with some diodes to bring it down to 3 - as previously posted (regarding 5v usb - post #7 BobA).


The usb powered one for $10 shipped hardly makes it worth messing around with (unless you happen to enjoy that sort of thing).

modified: doh, posted before seeing your last post.  Let us know how you work it out with the usb powering up/down or with powered hub, etc.

[DrumAnBass]

Yah the concept of running my own pirate radio station always appealed to me- hence my interest in those Ramsey's... But also the thought of sending a good powered FM signal throughout my house, backyard, my neighbor's backyards etc sounded fun too.

But anyway, those dealextreme ones seem promising too.

[muzland]

Placed an order for one of these as well.

A grand total of £4 including shipping.

Even if it is crap it still a bargain.

Muzland

[_) (V) (-)]

I've got one ordered as well.
The ghetto blasters are in for a treat, hee hee.

[unclet]

Well, I just got mine delivered today and there was no USB cable included.   There is only an adapter which plugs into my car cigartte lighter.   I guess I should have looked into this a bit harder.

It seems like it has a tiny small hole in the back which it states is for USB, but I guess I need a specific cable for that.

1) Does anyone have the correct cable they are not using and would care to send it to me?

or

2)Will someone tell me how to hack off the cigarette lighter plug part and connect a plug adapter to it?  It states the wroking current on the device is "30mA   1.5V x 2 AAA Batteries"

[EwJ]

Is it possible the tiny hole in the back is for a mini-usb connection - like the ones some mp3 players and other small usb devices use?  Post a pic.

[EwJ]

If so, it's a standard, readily available cord.
like so, miniusb

That's not really a clear pic, but you can see the small end is approx 1/4 the size of the regular usb end.

[unclet]

My wife happen to find a USB to miniUSB cable she uses for her digital camcorder and that cable does not fit the FM transmitter.    Checkout the picture attached to see what the attachment looks like

[EwJ]

From the previous posts, it looks like tba and psychotech both had theirs powered by usb. Perhaps they will comment, if not, you could try a pm to see how they hooked theirs up. 
That may be a micro-usb connection (not a mini-usb), if you have one of those cables around somewhere, give it a go.
What cables did it come with? 
If you got a car adaptor cable with it, and it has that micro(?) usb end on it, you could probably cut it off and splice it to a regular usb cable to hook to your pc (or hub).

[unclet]

It only came with one adpater plug which is meant to plug into a car cigarette lighter.  The picture below shows you what the end of this adapter looks like.   Is this a micro-USB end piece?

[EwJ]

Not 100% sure, but looks like it:
usbtypes

If so, you just need to pick up a cable if you don't have one there.  If not, looks like you could probably cut it from the cig adaptor and splice it into a regular usb cord?

[unclet]

It kind of looks like the one all the way on the left.   Is that a "micro-USB" cable?

[Namco]

The one you have is a USB 4-pin Mini-B. The trapezoidal shaped ones are 5 pin. I see it alot on newer MP3 players. They seem to be a replacement for the old Mini-B 4pins that were shaped like a capital D back in the USB 1.1 days. Been around for a couple years already.

The picture that's referenced shows a new Micro USB connector on the far left. It's a brand new shape that came out recently. I haven't seen one in the wild yet.

[unclet]

Ok, then I will look to buy a "USB 4-pin Mini-B" cable .....

[brandon]

you could alway connect the cig adaptor to the +12v on the PC power supply...