Hi all,
We have a doubt about the tuning of the RF transmitter/receiver
If I have 10 of that how can avoid the interferences between them?
Is it possible to tune the the transmitter?
Thanks
Onde
No, the receiver receives already a certain band. I don't know how wide it is. But I have the same receiver and it receives frequences near the 433.92 MHz from different devices which are at slightly different frequencies.
As far as I know, the transmitter is allowed to sent during 10% of the time. Most devices sent the message a few times. Mayby 10 to 20 times.
You could use an extra byte as a identifier, so the receiving Arduino can test the identifier.
The VirtualWire library can be used with those.
The receivers are approx 4 Mhz wide centred on 433.92 , and will receive anything within that range.
They cant be tuned.
Thank you so much for the replies.
We are waiting for the shipment arrivals.
In the meantime let's start to look for VirtualWire library.
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but the main question is :
We will have independent control of each transmitter/receiver ?
Bye
Onde
You will have 1 transmitter sending "stuff" to 10 receivers? That will work fine with virtualwire. Include an "address" as part of your message so that a receiver knows when a message is intended for it. And perhaps a "global address" that all receivers do something with.
That is up to the software protocol.
For example, the first byte could be an identifier as I wrote.
The transmitter transmits the identifier, and the receiver only accept messages with the right identifier.
If two transmitters start transmitting at the same time, they get mixed. But the VirtualWire library uses a CRC check, so it will not be received. That is why the transmission should take less than 10% of the time and the messages are transmitted a number of times. But I already wrote that too.
(CrossRoads replied while I was writing this. He says the same, using an "address" (or "identifier") is the normal solution).
We will have independent control of each transmitter/receiver ?
No.
Only one transmitter can transmit at any one time. What it sends will be picked up by all receivers.
Transmitting at the same time as receiving is a difficult thing to do.
In the world of ham radio repeaters of around 145MHz have a difference in transmit / receive frequency. They require very sharp cavity filters to keep the transmitter out of the receiver, these are physically large. At the ham bands of 440MHz they use a difference of 5MHz and again heavy filters.
Well , Onde. I have looked through what you bought. It is a simple ASK transmitter/receiver. It is negative for 10 units working simultaneously. Because we have the same channel in order to interference with each other. So i suggest you get wireless transceivers which can adjust the working channels. Moreover it is a little expensive than what you have bought.