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Bluetooth and Radio Frequency?

Electronics.Lover

Jul 26, 2014
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Hi, I am having a concept here and I would like to know whether is possible to work or not. I would like my smartphone to be connected to a bluetooth receiver and then I want the data to be transformed into radio frequency wave.

Hence, my car radio receiver will be able to play the song from my smartphone. I hope you get what I meant. In summarized,
Song from smartphone -> bluetooth receiver -> radio freq transmitter -> my car radio freq receiver.

For your information, my car is a old car, no built in bluetooth device.

I am having a Arduino Uno and I am new to it. Any advice or guide or reference to get my project started off?

*Please help me to think a suitable title fpr this thread*
 

BobK

Jan 5, 2010
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You can by FM transmitters that plug into the headphone jack and do exactly what you want. No need for Bluetooth.

Bob
 

Gryd3

Jun 25, 2014
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If Bluetooth is absolutely required... you may have to link a 'Bluetooth to 3.5mm' adaptor to an FM transmitter mentioned by Bob.
You may get lucky and find a product pre-made, but I have not seen them yet.
 

Electronics.Lover

Jul 26, 2014
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You can by FM transmitters that plug into the headphone jack and do exactly what you want. No need for Bluetooth.

Bob

The bluetooth is to make the song play wireless-ly without any cable attached to my smartphone btw. With a cable always attached is quite troublesome.
 

Electronics.Lover

Jul 26, 2014
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If Bluetooth is absolutely required... you may have to link a 'Bluetooth to 3.5mm' adaptor to an FM transmitter mentioned by Bob.
You may get lucky and find a product pre-made, but I have not seen them yet.


Yes there is no such pre-made, yet maybe. So I am thinking of making myself one and at the same time learn how it works too.

Arduino + Blutooth module HC-06 = 3.5mm jack

3.5mm jack + RF transmitter = songs get played in my car from my smartphone :D
 

Electronics.Lover

Jul 26, 2014
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I just started reading this guide today. So far so good. I hope this will guide me to finih this projects. Any advice, opinion, guide suggestion, knowledge sharing and so on are extremely welcomed :)
 

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BobK

Jan 5, 2010
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Even if you get phone - Bluetooth - Arduino working, you will either need an external DAC or be satisfied with fairly low quality sound.

Bob
 

Electronics.Lover

Jul 26, 2014
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Even if you get phone - Bluetooth - Arduino working, you will either need an external DAC or be satisfied with fairly low quality sound.

Bob

Thanks Bob for telling about the requirement of DAC :)

Anyway, I would prefer step by step and one by one. I would like to start with the section of 'phone - bluetooth - Arduino' , is this very tough? Any example or tutorial to guide me?
 

Gryd3

Jun 25, 2014
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Thanks for sharing anf that's cool :D but unfortunately, it's too expensive for me. I would rather DIY one. Any idea to DIY it?
Buying an Arduino, a Bluetooth module that supports at least A2DP and the time involved to hook it up is going to be more expensive IMO.
However, if you really want to go digging into this. Your first step should be to track down a Bluetooth Module that supports A2DP otherwise you will either not get any audio, or your audio will sound like crap.
Do you plan to do any audio processing with the Arduino, or was this just something you thought was required for the bluetooth module?
Do you plan to build your own FM transmitter as well, or will you buy one?
Alternatively, keep your eyes open for a bluetooth speaker or headphones. Old models go on clearance for $5-$10 and can be cracked apart. You can then use the internals and hack them together to an FM transmitter.


Arduino + A2DP question -- tl;dr: Dont use the Arduino for the audio.
http://forum.arduino.cc/index.php/topic,122886.0.html
 

BobK

Jan 5, 2010
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Alternatively, keep your eyes open for a bluetooth speaker or headphones. Old models go on clearance for $5-$10 and can be cracked apart. You can then use the internals and hack them together to an FM transmitter.
I think this is the best idea yet.

Bob
 

Electronics.Lover

Jul 26, 2014
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Buying an Arduino, a Bluetooth module that supports at least A2DP and the time involved to hook it up is going to be more expensive IMO.
However, if you really want to go digging into this. Your first step should be to track down a Bluetooth Module that supports A2DP otherwise you will either not get any audio, or your audio will sound like crap.
Do you plan to do any audio processing with the Arduino, or was this just something you thought was required for the bluetooth module?
Do you plan to build your own FM transmitter as well, or will you buy one?
Alternatively, keep your eyes open for a bluetooth speaker or headphones. Old models go on clearance for $5-$10 and can be cracked apart. You can then use the internals and hack them together to an FM transmitter.


Arduino + A2DP question -- tl;dr: Dont use the Arduino for the audio.
http://forum.arduino.cc/index.php/topic,122886.0.html

A2DP stands for?

Yes that was something I THOUGHT that needed for bluetooth module? Is it not necessary for this project? Do correct me if I am wrong :)

Maybe I will make one. I would leave that aside first as I am think of building a Bluetooth receiver with 35mm stereo female connector first. (Then a FM transmitter with 35mm male connector to connect with the Bluetooth receiver).

And thanks for the link to the Arduino Forum :D
 

Gryd3

Jun 25, 2014
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Depends on how deep you want to go...
You can work with something like this if you want to build it completely yourself
http://www.microchip.com/wwwproducts/Devices.aspx?product=RN52
http://ww1.microchip.com/downloads/en/DeviceDoc/rn-52-ds-1.1r.pdf

You wont be able to make a Bluetooth receiver completely from scratch... You will end up investing countless hours in developing a circuit to operate on the proper frequency, then will need to create a firmware for the circuit to properly handle the required Bluetooth Profiles you want.
You will need to use pre-built radios at the very least like the one linked in this post. You will still need to do a bit of work to use it, but it's closer to 'building it yourself' than the other method.
At least with buying and ripping apart an old/discontinued bluetooth speaker/headphones you will already have a complete circuit to use... just tap into the button to pair your device, and tap into the audio out.

The bluetooth device in your project is only going to fill a very basic role. Why complicate things?
 

Electronics.Lover

Jul 26, 2014
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Depends on how deep you want to go...
You can work with something like this if you want to build it completely yourself
http://www.microchip.com/wwwproducts/Devices.aspx?product=RN52
http://ww1.microchip.com/downloads/en/DeviceDoc/rn-52-ds-1.1r.pdf

You wont be able to make a Bluetooth receiver completely from scratch... You will end up investing countless hours in developing a circuit to operate on the proper frequency, then will need to create a firmware for the circuit to properly handle the required Bluetooth Profiles you want.
You will need to use pre-built radios at the very least like the one linked in this post. You will still need to do a bit of work to use it, but it's closer to 'building it yourself' than the other method.
At least with buying and ripping apart an old/discontinued bluetooth speaker/headphones you will already have a complete circuit to use... just tap into the button to pair your device, and tap into the audio out.

The bluetooth device in your project is only going to fill a very basic role. Why complicate things?

Thanks Gryd3, I thought building a Bluetooth receiver is not a very complicated thing but forgive me, I'm wrong. Let say if for now, I am using this (I saw this Bluetooth receiver 2 days ago at a electronic shop), as the receiver directly from my smartphone. *I would use pictures to express my thoughts in the following messages*
 

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Electronics.Lover

Jul 26, 2014
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Do you think will my concept works?

My aim is to make a device/system which can transmit radio frequency to my car RF receiver so that songs can be played directed from my smartphone through my car speaker.

And I got a few RF transmitter circuit, which I get from different website. BUT for now, I need to know how to make the DIY 1 - which it need to read the data from the Bluetooth receiver then? Please help..
 

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Gryd3

Jun 25, 2014
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Do you think will my concept works?

My aim is to make a device/system which can transmit radio frequency to my car RF receiver so that songs can be played directed from my smartphone through my car speaker.

And I got a few RF transmitter circuit, which I get from different website. BUT for now, I need to know how to make the DIY 1 - which it need to read the data from the Bluetooth receiver then? Please help..

If you want to use that USB bluetooth adaptor. the only thing I can think of is using something like a raspberryPi for DIY1...
or you will need to program a microcontroller to be able to act as a USB host, and write your own driver for it so it can properly talk to the USB bluetooth module. You will then need to take this digital data and turn it into an analog signal with a DAC to feed to DIY2 (FM transmitter) This is quite involved, and most likely not worth the effort unless you plan to mass a large quantity to sell.

I know exactly what you want to accomplish:
You want to be able to pair your phone with this device via bluetooth so that this device will retransmit the audio over FM to your car stereo.
 

BobK

Jan 5, 2010
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I think you should look again at post #11 for the only solution you are likely to succeed with without months of effort.

A pair of Bluetooth earphones has the Bluetooth transceiver and DAC already working. All you need to do is plug the audio out from it into an FM transmitter which you can get for a few bucks on Ebay.

Bob
 
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