One audio (Stereo ) master transmitter to multple audio reciver.

[thannara123]

Hai Experts ..


I am plan to a project where One audio to (Stereo ) master transmitter to
(about 8 reciver ,where it recives setero ) multple audio reciver.


How to lay out the project . i think Bluetooth is not enough for it .
(product cost will be minimal )


Please give me a guidelines and suggestions .

 

[betwixt]

The cheapest way will be to use an FM stereo transmitter and normal stereo FM receiver.
A two transistor FM transmitter fed with the output of a BA1404 IC comes to mind. There are several alternative ICs.

Brian.

 

[BigBoss]

Silicon Labs has few very effective transmitter ICs.They transmit in FM band with stereo feature.

 

[KlausST]

Hi,

In your post I see not much information....I don't even see the requirement for wireless. Analog, digital? Resolution? Dynamics, quality, expected delay between receivers?

Why not use ready to buy ones? What's the idea behind it?

Klaus

 

[BradtheRad]

Personal earbud FM receivers are available for 5 or 10 dollars. It's easy to press the wrong button, and an usher might have to assist listeners who lose the transmission.

If you can accept monaural sound, consider a karaoke microphone (or 'Mister Microphone') which transmits to nearby FM radios.

For ease of use we purchased headset walkie-talkies on a fixed frequency (49 MHz). These were a step better than the usual squawky-talky. About $50 a pair from a mail-order supply (mid 1980's). We converted one set to mic only. For the other 3 sets we removed the mics, and disconnected the 'transmit' switch. Our system worked well for years. Maintenance consisted of seeing each was turned off afterward, and checking 9V batteries occasionally.

 

[thannara123]

The stereo audio transmitted to diffrent loactions(rooms) .
Bluetooth can only connect only one .
How to multiple ?
Can i to send the data digitally ? Is it much more complex ?
It need to be transit upto 320kbps ?

 

[betwixt]

Bluetooth can only connect only one .

That is what Bluetooth is for, short range personal communication.

How to multiple ?

I'm no expert on this but I don't think it will work.

Can i to send the data digitally ? Is it much more complex ?

Yes, considerably more complex. Consider RTSP or some other streaming protocol via WiFi.

It need to be transit upto 320kbps ?

I'm not sure if that's a question or requirement. The data rate basically sets the quality you hear but bear in mind that CD quality is only 44.1KHz sampling rate.

Brian.

 

[BradtheRad]

There are wireless stereo headphones which operate by radio. The signal goes through walls (although maybe not through 8 walls). Each set comes with a base unit which accepts stereo audio input. Mine gives a choice to transmit on three channels around 900MHz.

You could buy 8 sets and transmit to all 8 from one base unit. $20 for inexpensive type.

- - - Updated - - -

I place my headphones on the base unit to recharge the AAA cells.

 

[ads-ee]

If you search for "multiple wireless headphone system" you might get some ideas of what systems are out there, they aren't done with bluetooth they are all either FM or IR for the mulit-user TV type headphone systems. A lot of the multi-user FM systems are designed for classroom usage and can have way more than 8 headphones.

If you are looking for cheap then you can go the route that Brad suggests and get some of the cheap TV types (some of which are FM). Saw one that had 2 headphones, so you would only need 4 sets.

 

[thannara123]

There are wireless stereo headphones which operate by radio. The signal goes through walls (although maybe not through 8 walls). Each set comes with a base unit which accepts stereo audio input. Mine gives a choice to transmit on three channels around 900MHz.

You could buy 8 sets and transmit to all 8 from one base unit. $20 for inexpensive type.

- - - Updated - - -

I place my headphones on the base unit to recharge the AAA cells.

Can i make it or may i get the details 900MHz based one ?

- - - Updated - - -

As the above experts suggestion i concluded that it can be make by using FM stereio reciver module like https://www.fabtolab.com/grove-i2c-fm-receiver

But I have question that can i make it private ? ,ie can i it decoded ? or no one recive with it pls suggestion ?

 

[betwixt]

Making it private is not something you asked for before.

The range can be quite short, that gives some restriction on who can listen but any receiver in range will hear it as though it was a normal radio station. Why do you need it encrypting?

Brian.

 

[BradtheRad]

Can i make it or may i get the details 900MHz based one ?

There are IC's available as the basis for an FM receiver, by adding a few components. LM1800 is an example although I don't know if suits your purpose. You might find complete kits on Ebay if you feel like taking a chance.

The antenna needs to be turned to the transmitter frequency precisely. That means you must tune 8 antennas.

To build a stereo FM transmitter is a big challenge.

* Its transmitting frequency needs to be stable.

* The antenna needs to be tuned.

* Your tranmistter must not broadcast harmonics that might cause EMI interference to your neighbors.

* Your frequency must be within allotted bands of the spectrum per local regulations.

So it seems easier to start with one commercially manufactured transmitter, and build 8 receivers.