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All things pertaining to wireless and RF links
By whitehat09
#120327
Hi,
Im an Electrical engineering student and am trying to start some small projects for myself but have little experience and need some answers.

I have an old mp3 player that is small so its good for jogging, but I hate the dangling headphone wires. I was thinking of implementing a small bluetooth transmitter that could connect to a set of store bought bluetooth headphones. I came across the BTM182 (http://www.sparkfun.com/products/9977) and thought that would be a good starting point. Since I just want it to transmit music all I would need to connect is a power supply and the audio signal right? Or is it more complicated than that? Could I use this chip by itself or would I need a small microcontroller like an arduino?

Thanks
By whitehat09
#120355
whitehat09 wrote:Hi,
Im an Electrical engineering student and am trying to start some small projects for myself but have little experience and need some answers.

I have an old mp3 player that is small so its good for jogging, but I hate the dangling headphone wires. I was thinking of implementing a small bluetooth transmitter that could connect to a set of store bought bluetooth headphones. I came across the BTM182 (http://www.sparkfun.com/products/9977) and thought that would be a good starting point. Since I just want it to transmit music all I would need to connect is a power supply and the audio signal right? Or is it more complicated than that? Could I use this chip by itself or would I need a small microcontroller like an arduino?

Thanks
To be a little clearer, I would like to design a small external Tx. So I plug it into the headphone jack on the mp3 player and power it by either the usb port or a battery.
By whitehat09
#120554
Ok, so after doing some digging I've realized I need a BT module with A2DP capabilites so if any one knows of a cheap IC please let me know.
By Chinasaur
#121675
Glad you figured that out. I have one probably not good suggestion which is that if you really want to keep cost low you could look at a module that only supports headset protocol and not A2DP. Obviously the sound quality will be much much worse. Another problem is that most chips supporting only headset protocol do not include the audio codec so you would need to do more processing before sending audio data to the module.

For an A2DP module I can recommend the BlueGiga WT32, selling at SemiconductorStore for $33. You probably want the one with iWrap4 and internal antenna, so: http://www.semiconductorstore.com/cart/ ... duct=44694

Note however that this module is surface mount so you would have to get/design a board to interface with it. You might try asking SparkFun if they can sell you just the board for their breakout of this module. Or you could just buy the $90 product from SparkFun that is already on the breakout board: http://www.sparkfun.com/products/8952

I doubt you'll find a cheaper module that incorporates the audio processing, so unless you can somehow access an internal digital audio line on your mp3 this is probably the best you can do.

Bluetooth is fun to play with, but can be pretty frustrating. I have a Bluetooth project (microcontroller talk to Android phone) waiting to finish because I found out that the bluetooth support in the Android stack is terrible so I have to write my own Android software to finish the project.
By Chinasaur
#121676
Couple last notes. I am considering designing a breakout board for WT32. I made a breakout for WT12 that's available on BatchPCB and works fine. Would be nice if SparkFun would release the design files for their breakout, but doesn't seem like they want to.

Finally, I believe there are some commercial products that fill your niche. They're hard to search for; you tend to get a lot of bluetooth receiver to audio instead of audio to bluetooth transmitters. But they are out there. Not as fun though I know...
By stevech
#121704
whitehat09 wrote:Hi,
Im an Electrical engineering student and am trying to start some small projects for myself but have little experience and need some answers.

I have an old mp3 player that is small so its good for jogging, but I hate the dangling headphone wires. I was thinking of implementing a small bluetooth transmitter that could connect to a set of store bought bluetooth headphones. I came across the BTM182 (http://www.sparkfun.com/products/9977) and thought that would be a good starting point. Since I just want it to transmit music all I would need to connect is a power supply and the audio signal right? Or is it more complicated than that? Could I use this chip by itself or would I need a small microcontroller like an arduino?

Thanks
Easiest by far is take audio from earphone jack, feed to teeny FM broadcast transmitter. Then use wireless headphones with an integral FM broadcast receiver. With digital such as bluetooth, you might have a lot more work to do. Depends on if this is an adventure of learning or just get to a convenience item quickly. Also Bluetooth's limited battery life.
By whitehat09
#121742
Thanks everyone for you replys.

I the bluegiga was exactly what I was looking for but unfortunately I already purchased a used scosche IUBTT audio transmitter on ebay, but I will keep the WT-32 in mind for future projects. I prefer bluetooth over FM mostly because of noise issues with FM and going through a bluetooth project would be helpful for future interests.
By Franky
#122456
Yes, its definately possible to make this by Bluetooth but only if you really like it as a hobby, otherwise it would be much faset and easier to use a cheap FM transmitter.
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