RF digital data receiver 433 Mhz low noise with 4049
tohu
Posts: 3
Hi everybody,
How can I build RF digital data receiver 433 Mhz low noise with 4049?
Thank you
How can I build RF digital data receiver 433 Mhz low noise with 4049?
Thank you
Comments
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I'm not sure if a 4049 is going to be fast enough for 433MHz...· but you might be able to work something out with a couple of discrete mosfets to form·a half-bridge amplifier.
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I have used a 4069 hex inverter in the past for much lower RF frequencies and·A 4049 should work just the same for lower frequencies.· The trick is to force the inverter into it's linear operation mode·by tying the output to the input with a resistor.· The resistor value should be extremely high 10Meg or so.· What this does is basically create a broadband RF amplifier. ...try it! ...scope the output and connect an antenna (6 inch piece of wire) on the input.· You can add more stages by using a 10pf capacitor to couple the output from one inverter to the input of another inverter (<-Each used inverter stage should have a·10 Meg resistor·across the input and output of that inverter).
·
Tie ALL unused inverter inputs to GND
·
Note: You could probably use a half-Bridge motor controller IC also for this (check the rise and fall times)
·
All of this works, but it's not tuned.· In order to tune it, you·need an LC tank on the first input stage inverter that corresponds to the frequency that you want to detect.
·
Once you have done that, you now have a tuned RF·detector.· You still need to decipher what the data is doing at your frequency of interest.
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Why not use a product that does all of this for you?
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http://www.parallax.com/detail.asp?product_id=27980·- 433MHz Transmitter
http://www.parallax.com/detail.asp?product_id=27981·- 433MHz Receiver
http://www.parallax.com/detail.asp?product_id=28180·- 433MHz Transceiver
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
Post Edited (Beau Schwabe (Parallax)) : 9/28/2007 8:06:38 PM GMT
I build a project IR remote control transmitter and receiver RC5 protocol with PIC16f628, and I want to make it RF remote control with digital ICs and transistors.
In the transmitter I send the signal with transistor ss9018.
In the receiver I process and amplify the signal with 4049.
But the signal distorts so that the led in my receiver that indicates·that signal received·run and refer to it's not RC5 protocol and·the (PIC) receiver ports didn't response !!!
Post Edited (tohu) : 9/30/2007 4:05:16 AM GMT
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
In the transmitter I send the signal with transistor ss9018.
In the receiver I amplify and modulate the signal with 4049.
But the signal distorts so that the led in my receiver that indicates that signal received run and refer to it's not RC5 protocol and the (PIC) receiver ports didn't response !!!
Note:
The kinds of 4069 ICs in my country is very bad and some of them have 16 pins !!!
This is my schematics:
Your setup looks like a typical regenerative style receiver.· The 4049·is there to condition the signal.· By your earlier post, the assumption was that the 4049 was actually receiving/detecting the signal.· What happens if you use an even number of inverter gates on the receiver end?· I would think that the odd number of inverters might cause the circuit to oscillate, where with an even number it would form a schmitt <- commonly used when receiving data.
Are you able to "scope" the receiver?· If you were to remove the 4049, what does the received signal look like between the 100K and the 10Meg resistor?
·
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
Post Edited (Beau Schwabe (Parallax)) : 10/1/2007 2:33:13 AM GMT