BT module with Audio Module

[scarr999]

Hi,

I am trying to make a audio module that has BT to connect to a pair of small speakers. I also require inputs to activate selected sounds.

Here are the two modules I am using.

https://www.ebay.co.uk/itm/275225937591

https://www.ebay.co.uk/itm/193525989771



I pair the two speakers and test it using my phone, it connects and I can hear sound out of both speakers (with only one BT connection from my phone.

I turn off my phone BT, Connect the audio module via the BT module to the speakers but only get sound out of one speaker.

I have changed the connection to the BT module from R to L channel and I get a clicking,

I linked R and L together with solder and I get distorted audio

I changed pads on the Audio module from L to R and again tried a the single channels and them linked together

I tried adding both L and R channels from audio module to BT module with a common gnd and that failed.

After all that I re-tested the phone and it works without issue.

I also have used a brand new BT module, same results.


Anyone any ideas?

[Buriedcode]

I'm not clear one xactly what the setup is.  To me it reads as: 

You have a bluetooth "transmitter" module, an audio module and two bluetooth speakers. 
You tested the (bluetooth) speakers using your phone, and sound plays out of both speakers.
You wish to connect your audio module, to your bluetooth module, to connect to the bluetooth speakers, to play sound.

Are your bluetooth speakers "one unit", as in, on bluetooth device, with two speakers attached, or are they two seperate bluetooth speakers, meaning that the tramitter needs two connections?
It could be that the transmitter cannot connect to multiple devices, but just one "sink" that recieves stereo audio.  So it can only connect to one speaker at a time.

Note: I am unfamiliar with all the modules you mentioned.

Edit: I noticed the audio output of the MP3 module appears to be differential - it has no common ground it drives both ends of the speaker, rather than have one output a the other ground. So powering  these modules from the same power supply, and then connecting the speaker output to GND and the audio input of the BT module will short that amplifiers output, and the other output will be floating at half the power supply voltage.  It is designed to drive a speaker, not a single output referenced to ground, at least thats how most 8 pin audio speaker drivers work.

[tom66]

It's possible your BT audio module is in Headset Profile mode (for phone calls) which is mono only, and you need to get it into A2DP mode - assuming it supports that!