RF module

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RF module

Postby suhaila38 » Fri Jan 22, 2010 1:50 pm

I bought your RF module to build my circuit and used PR16 as a reference.My question is:

1) Referred to the PR16's circuit,the transmitter also include with the transistor,but,when I bought it,it don't have. Why?? :roll: Do we need to put it by ourself? What is the function of that transistor?

2)Is the circuit for PR16 also contain noise? :?:

3)By using the RF module produced by Cytron, can we eliminated that noise? How to it? :?
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Re: RF module

Postby A380 » Fri Jan 22, 2010 4:40 pm

suhaila38 WROTE:1) Referred to the PR16's circuit,the transmitter also include with the transistor,but,when I bought it,it don't have. Why?? :roll: Do we need to put it by ourself? What is the function of that transistor?


No transistor found when i refer back the schematic. why you say that?

suhaila38 WROTE:2)Is the circuit for PR16 also contain noise? :?:

3)By using the RF module produced by Cytron, can we eliminated that noise? How to it? :?


Is depend on the environment. I think the given sample program don't have a good digital filter. You should do your own filter (in software) to prevent the noise from the environment.
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Re: RF module

Postby suhaila38 » Fri Jan 22, 2010 5:59 pm

what shown in the schematic is just the layout..for example,u can't see the resistor on the receiver..i think u should see the datasheet for PR16..nt the schematic.

i have done my own coding to transmit the data using that RF module.unfortunately,some times, the receiver will receive 'garbage data'..if u don't mine,can u guide me to do the coding for noise filtering...i already go through many website,but can't find the appropriate way to solve that problem...maybe,u can give the idea... :P
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Re: RF module

Postby waiweng83 » Sat Jan 23, 2010 10:53 am

suhaila38 WROTE:1) Referred to the PR16's circuit,the transmitter also include with the transistor,but,when I bought it,it don't have. Why?? :roll: Do we need to put it by ourself? What is the function of that transistor?


The RF Transmitter with transistor is the old version. There is no transistor in the latest batch of the RF Transmitter. However, the functionality is still identical.

suhaila38 WROTE:2)Is the circuit for PR16 also contain noise? :?:


Yup, the PR16 will have interference problem as well sometimes.

suhaila38 WROTE:3)By using the RF module produced by Cytron, can we eliminated that noise? How to it? :?


This is the nature of the low cost RF module. You will need to implement the noise filtering algorithm in your software such as including Checksum or even CRC in your data packet. However, we don't have the sample source code for this moment.

Alternatively, you can also try to lower the baud rate of your UART. This might improve the performance a bit.
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Re: RF module

Postby suhaila38 » Mon Jan 25, 2010 4:54 pm

Thanks for ur answers :D
for my project, I send 8 bits of data as the ID for each device to be active.

For example, when the push button 1 is pressed, 8 bits data, ie "0b00110011" will be sent by the transmitter and received by the receiver containing the same ID and the device will be ON. I have tried to send 2 different data for 2 receivers containing a different IDs using the 1 transmitter only .It works! Unfortunately, it contains noise.

From your explanation, I've got to filter incoming data to the receiver rite? Meaning, the data received by the receiver will be managed by using the CRC technique before it activated the device.

Correct me if I'm wrong.. :geek:
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Re: RF module

Postby waiweng83 » Wed Jan 27, 2010 11:40 am

The CRC or checksum is to make sure your data is being received correctly. It's not to encrypt your data. You need to send your data in a packet instead of just single byte. For example, you may design your packet as 4 bytes like below:

<Packet Header> <Device Address> <Data> <Checksum>

The checksum = Packet Header + Device Address + Data

So at the receiver side, if the calculated checksum is different from the checksum sent by the transmitter, then you can know that some part of the packet is corrupted.
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