433 Mhz Data Receiver

[Pesticida]

Hi people,I have found a 433 Mhz data receiver the chip on the receiver is a Philips UAA3201T like on the photo .
From pin 9 I receive the data,my question is how I must connect this pin to my PIC 16f870 and what command I can use to read the data.
I tryed with serin porta.0,n2400,B0 on porta.0 but I receive a lot of data .
This 433 Mhz receiver have a standalone "Button" transmitter ,I want to display the data from this little transmitter example on my PC.
To interface between my pic and my pc is not a problem,just between PIC and the receiver is a problem for me.
I have on the pin 9 on the receiver 1 volt when i push the "button" transmitter i have on the pin 9 2.5 Volt of data.

Thanks.
bye Pesti.

[NavMicroSystems]

Pesti,

those "Single Button Transmitters"
(ie. Wireless Door Chime) usually consist of a very simple RF transmitter and an encoder chip.

There is actually not much data of any sense to be displayed as long as you don't know in detail what the transmitter is sending and how it is encoded.

(Or are you trying to "Sniff" the bitstream and "Clone" the transmitter?)

[Pesticida]

Hi,
:-) Is not a Wireless Door Chime,I have one alarm button transmitter and a receiver.
Now I want to read the data from this button and make my own circuit with a PIC16f870.
The problem is I can not read the data from the original cicuit PIC16f84 and receiver.I want to receive data from receiver to pic and then I can see what code send this button.
I can write my own visual basic program with this "code",when i push the button something happend on my program, alarm is incoming and so on.
I hope you understand what I mean.

Bye Pesti.

[Ron Marcus]

The receiver is a simple OOK receiver. Do you already have a companion transmitter? I once took apart a similar device that was part of a IR proximity alarm. It would sense a warm body, and send out a 24 bit stream of data which included it's address, and the alarm state. I reverse engineered a receiver for it that looked at the incoming noise for a particular pattern of data. For instance, let's say that the transmitter put out four short bursts and four long bursts to indicate it was in an alarm state. The receiver looked for a burst of the proper length. If it got it, it looked for the next, then the next, until all matched up in the right order, and each individual pulse was the right length. If for some reason, the pulse length or position was wrong, it fell through to the beginning. If all was right, and I got three correct sequences in a row, I had an alarm state, and the microprocessor put out the proper response.
With the receiver you have, the data slicer is going to be constantly transitioning from 0 to 1 and back again due to random noise. You need to be able to differentiate the signal from the noise. Most OOK systems that transmit data, will start with a preamble that will set the data slicer to the midpoint. Following this is a character that tells the receiver to listen up, then it's followed by the data, and a checksum so the receiver has some form of error detection. In your case, three characters repeated over and over will be enough to signal to the receiver what is going on, as long as they are relatively balanced between ones and zeros. Manchester encoding takes care of this for you, but it raises the level of complication above what you need.
I have used the Micrel receivers in the past for this, and have found them much easier and cheaper to use than the Philips parts.

Ron

[Pesticida]

Hi,
yes I have a receiver and a transmitter.
The receiver is connected trough a RJ11 cable to a PIC controller,now when I push the transmitter button the first time the PIC save the data from the transmitter to the pic memory,and now I can use the button with this receiver and PIC.
Do you understand what I mean.
I looked on the receiver,I receive all the time data from all buttons what I have but the PIC can just switch the output when I push the button what I have saved .
The PIC Schematic look like this,I draw just what I need.
My question is how can I do the same cicuit on my PIC 16F870 and what command I need to do this.I connect the receiver to my PIC but I receive all the time strange data and when I push the button I receive data to, but is all Mixed.

Thanks Pesti.

[Pesticida]

Ok,I read now the data from the PIC16F84 eprom.
When I push the button 1 and save the data trough the receiver to the PIC I can see on the adress 0000: 01 00 03 EF 36 00 00 00 when I push the button 2 I can read on adress 0000:01 00 03 ED 2E 00 00 00.
I think this is the right code!

Bye Pesti.