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Audio Streamer for Hearing Device - NEED HELP/ADIVCES

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Audio Streamer for Hearing Device - NEED HELP/ADIVCES

Postby Ospreys » Thu Feb 21, 2019 6:52 pm


To those who are reading this post, I need your help! I’m sure I will find here experienced and skilled people willing to give me a hand with this project.

First, I’m French, and even if I’ll do my best to write correctly in your language, I do apologize for my inevitable spelling and grammar mistakes.

My project is the following: build a “streamer module” which main goal is to do the connection between multimedia devices (smartphones, TV, radio) and noise-amplification ear plugs (small earplugs used by senior and hearing-impaired person).
For example, if the hearing-device user want to connect his/her hearing device to his/her smartphone, he/she needs an intermediary module making the link between the two.

Alright, now let’s get down to business.

You will find below the translation of a part of my design brief summarizing all the input and output connections of the module. And to spice things up, the streamer module needs to by inside a paralepidid of 8x8x4cm.


I started my project on searching for audio stereo Bluetooth module (like this one: to perform the Bluetooth <-> Jack 3.5mm connection.
Unfortunately, this one only does the Bluetooth  Jack 3.5mm connection and can’t go backyard. Moreover - as you can see in the table upward – I also need to do the Bluetooth <-> Bluetooth connection, and for that I need a full-duplex (receive and transmit at the same time) Bluetooth module (to use only one Bluetooth module, and not two).

Because I can’t find any pre-built audio stereo Bluetooth module that can go from Bluetooth to jack and vice versa, and perform full-duplex Bluetooth trans-reception, I abandoned this idea of using existing audio module.

Thus, I need to build my own audio board, with ADC, DAC, amplifier, Bluetooth module and so on. I know this is very complicated stuff (at least for me), therefore I am here to seek your advices.

In order the convert the analogic / digital audio data, I choose this audio codec: TLV320AIC3106-Q1. This is an automotive low-power stereo CODEC with 10 analog inputs, 7 analog outputs, HP amplifier and a max sampling rate of (96kHz enough for audio data converting). This one is from Texas Instruments.


As you can see in this functional block diagram, there are 10 analog inputs, 6 analog output and two digital pins at the top: DIN and DOUT (with their clock pins).

In relation with this module, my questions are the following:

- How will I be able to amplify the analog outputs (using the integrated amplifier but how, with which pins? Not matter how many times I read the datasheet, I can’t see this information).

- Do you think this audio codec is enough for my needs? I need to connect 3 different analogic devices (Jack, Induction coil, and Radio FM), but the datasheet says the module only has 2 different ADC channels. Well, I don’t understand it also says it has 10 analog inputs?

Using this audio codec, I can convert analogic audio data to digital audio data, and hopefully I can send those data to my Bluetooth transceiver module. I choose this module : RN4020-V/RM. This module has a data rate of 1MBPS (>192kbps which is the bit rate of the MP3 audio file). This module has an UART interface (RX and TX), but how am I supposed to send the digital audio data coming from my audio codec to the UART interface of the Bluetooth module? The only option I see is to use another module to make the link between the two… But what module, Arduino board?

I also looked at the RN4020-V/RM datasheet and I can’t see if this module can do full-duplex communication, receive and transmit at the same time.

I hope my explanations weren’t confusing… As you can see, I got myself involved in a project way to hard for my skills. But that is no reason to give up.

If you see anything odd or wrong with my way of thinking, please tell me.

Thank you so much for your help! You’re helping a young boy building up its skills, and this is priceless.
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Re: Audio Streamer for Hearing Device - NEED HELP/ADIVCES

Postby Sam Spoons » Thu Feb 21, 2019 7:31 pm

Welcome to the forum Ospreys :thumbup:

I don't really understand your chart for example the induction coil/loop is the output from the Loop Amp not the input, and hearing aids generally only have inputs (from either their microphone or the loop sensor 'Telecoil'). Not sure of any use for a hearing aid with an external output (except possibly as a phone interface).

So you really only need to send the signals one way, from the source to the hearing aid. Some modern hearing aids have a Bluetooth connection so to connect all those sources to all hearing aids you will need to send the signal to a hearing loop amplifier, a Bluetooth transmitter and, maybe, a 3.5mm jack output connector.

One source can supply those three destinations simultaneously so you just need a means of connecting the different sources easily to the BT transmitter and loop amp.
If both the source and hearing aid have BT you don't need to do anything, all the others would be better served by having an induction loop/coil with the appropriate inputs available so either a 3.5mm jack input and a bluetooth receiver. BT receivers are inexpensive and output on either RCA jacks or 3.5mm jacks so a simple two way switch box to select either the BT receiver or the 3.5mm cable would work (or, simply disconnect the cable from the BT receiver and plug it into the other source)?

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