Bluetooth streaming receiver - Page 1
Forum section: electronics / projects

author: showlyshah
author_rank: Newbie
timestamp: May 28, 2019, 07:38:27 pm
content: Hello guys.. i need a design help with Bluetooth device.. i tried to search google, posted on stack exchange.. but no use..my requirement is to build a Bluetooth receiver which can connect to Bluetooth headphones. any and all types of Bluetooth headphones/headsets. just like our mobile phones .. which should be able to receive.. ( no need of transmitting ) audio streams from Bluetooth headsets in live.. ( you know those rf mics and receivers.. thats the kind of function i am trying to get .. instead of the mic.. i want to use any Bluetooth headsets ) .i know some of these Bluetooth chips can act in walkie talkie mode.. ( which is half way through my requirement ) when two of the modules are paired to each other.. but its not exactly what i need.. i need 1 Bluetooth module + one general purpose mobile phone headset pairing .chip boards like csr 8645 seems good to me. mostly because i am looking for good quality audio.. but not so high end. aptx , low latency etc.. are most welcome. dont want to go through ldac or aptxhd.Thats all my concept.. now my concern is..why such a device doesn't exist? not even a reference design anywhere..audio latency.. i can manage few milliseconds.. but not so highi cant use complicated hardwares like extra microprocessors or controllers... if possible should embed everything into memory ic of such Bluetooth module.. and let the Bluetooth chip's inbuilt controller handle everything. all these because i am planning to make this receiver as small as possible.. with a 200-300 mah li-ion battery.some coding help , if any needed.. ( i am currently checking and learning csr chip configuration tool ) .. how to enable various Bluetooth profiles like hsp, a2dp etc.. and what exact profile is used by a Bluetooth headset to communicate with phone in a requirement for streaming audio ( from headset to phone ) and the possibility of enabling such a profile in these breakout board type Bluetooth modules.anything hardware based .. like opamps / power section bla bla bla.. i can handle quite easily.. oh.. this one may also require a small lcd to show avilable headsets for pairing..right? that possibly invites a smal micro controller too.... ok i can deal that too.i am pretty new to this Bluetooth programming thingy.. so any and all helps are most welcome..hope i can find some stepping stones from here..

author: Buriedcode
author_rank: Super Contributor
timestamp: May 29, 2019, 12:49:15 am
content: I'm unaware of anything regarding a "walkie talkie" mode. But there are bluetooth audio transmitters available fairly cheaply. You could probably modify these using a CSR-SPI dongle and the software, but the changes you will be able to make will be limited to user alerts, audio tones, the name of the device, and audio routing (on board preamps, I2S port etc..).If you require low latency, the lowest end-to-end latency I believe for aptx-LL is about 40ms max, which is better than the 80-120ms of standard bluetooth, but a few ms would require something other than bluetooth.It seems you require something that receives audio from headsets? Aside from the medium quality of the mic inputs used for headset profiles (mono, no stereo), I am unaware of any such device capable of that. Bluetooth audio was designed with one-way-streaming in mind, with feedback required only for voice (voice commands, phone calls etc..) so its a pretty asymmetrical setup.A project I was planning on doing sometimes (along with the 200 others on the list..) was a sort of medium area audio network for walkie/talkie headsets using NRF24L01's. But it's a lot of work to make a multicast protocol, with inteference avoidance, error detection/correction etc.. So rolling your own could get complicated very quickly if you go down the digital route.Were you planning on a 1 to 1 link? That is a small dongle for each headset?

author: showlyshah
author_rank: Newbie
timestamp: May 30, 2019, 07:16:48 pm
content: please refer the following link.https://learn.sparkfun.com/tutorials/understanding-the-bc127-bluetooth-module/allunder section hfp and pbap protocol.. you can see the walkie talkie mode. which enables bi directional audio.i dont even need bi directional mode. i require the Bluetooth module to be in some kind of master mode to accept pairing request from Bluetooth headsets.

author: Buriedcode
author_rank: Super Contributor
timestamp: May 30, 2019, 08:17:04 pm
content: So you require something that receives audio from multiple headsets? I don't think there is anything in the bluetooth spec for that, aside from a host connecting to two headsets for streaming audio TO those headsets. Sounds like you need something other than bluetooth.