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Looking for a very small transmitter/receiver

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Member level 3
Dec 31, 1999
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I'm looking for a circuit of a very small sized Transmitter/Receiver.
The transmitter should be able to send four different signals which four different receivers will be able to recive it and play some sound. I'm looking for the samallest possible receiver. the transmitter can be big.

The receivers will be able to receive only one of the four signals.
Lets say the transmitter has four button on it, each one to activate one of the receivers and the receiver will play some sound. I'm interested in making the receivers as small as possible less than 1 (in)sq.
This is what i'm thinking. the transmitter will transmit sound modulated at a high frequency (four different one for each receiver, depending on which button is pressed). The receivers will have a filter, demodulator and a speaker. This will make the receiver very small. the filter and the demodulator will the simplest one possible. this will eliminated the need for the sound signal to be stored the receiver.

I don't want to but them i want to make them I'm looking for the schematic, Any other design idea is welcomed.

<font size=-1>[ This Message was edited by: nitr8 on 2002-04-21 03:51 ]</font>

Hi Nitr8
I heard from my friend "in Japan they sell very small transmitter/receiver but I have some question for you
1 how much the baud rate or bit/sec
2 how long distance do you want to comunicate
3 what kind of power supply doyou use
if you show the information I will ask my friend.
Additinary japanese company MITSUMI they have small packaged TR/re product.This is an Bluetooth example
**broken link removed**
hopefully helpfull for you

The project is for a class.
The design is of a locator, to help find items like TV remote, cell phone or any other items one tends to loose often. It is to be used in an home environment. So limited range. The receiver can be stick to any item (TV remote etc), hence has to be small and lightweight. It should beside others things contain a small speaker. When a button on the transmitter is pressed, the receiver will beep. The transmitter can run of AA bateries because it will be mounted on a wall.
But the receiver has to be run of small round cells like in watches.
Again i'm interested in the schematic. if you friend can provide the schematic that will be cool. Any design that will fullfill my needs will be cool. it can be an FM transmitter/receiver or any other design.

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