433Mhz UART Module Arduino modification

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433Mhz UART Module Arduino modification

Postby TanRunEn » Mon Mar 02, 2015 11:08 pm

As most of us know, there is a 1k resistor on the 433mhz module so we will have to make changes to our code by changing tx rx pins. So if i desolder and remove the 1k resistor, will it work normally on arduino original tx,rx pin?
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Re: 433Mhz UART Module Arduino modification

Postby ober » Tue Mar 03, 2015 10:11 am

TanRunEn WROTE:As most of us know, there is a 1k resistor on the 433mhz module so we will have to make changes to our code by changing tx rx pins. So if i desolder and remove the 1k resistor, will it work normally on arduino original tx,rx pin?


Not really try that before, we have yet to explore where is the 1K resistor.

BTW, removing it will not work because the 1K resistor is in series with the TX. You need to remove and short it :)

Try it and let us know. Good hacking by the way.
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Re: 433Mhz UART Module Arduino modification

Postby TanRunEn » Tue Mar 03, 2015 6:58 pm

This might be one of the most frustrating hacks i ever made because when i found that i was unable to remove the 1k resistor so i just simply smear solder onto it but i found that it doesn't work, since i am not equiped with smd soldering, i use my sucker to suck out the solder but suck out the solder and the resistor instead. Luckily i got some surface mount resistor in my home so i try to solder them on but accidentally move some of the other surface mount component on it too. The component on the circuit board is all a mess. I think i might have lost RM120.
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Re: 433Mhz UART Module Arduino modification

Postby TanRunEn » Wed Mar 04, 2015 6:21 pm

Hey ober, i think something is terribly wrong with the rf module. I tidy up the component and it works but the range is only 20 meter for clear line of sight. I am transmitting at 4800 baud rate at 20dBm with the spring antenna soldered on it.
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Re: 433Mhz UART Module Arduino modification

Postby ober » Wed Mar 04, 2015 11:27 pm

Good to hear you learn new things and manage to tidy up.

Wireless module are really sensitive to antenna impedance and noise. We manage to get around 100 meters of communication with wall and cars around at 9600 baud with the given antenna. 1km is in the specification, they have a special way to carry out test like this. After you tidy up, I am sure the performance will drop. You are lucky to get it works :)

Same goes to XBee PRO, according to the spec, it is able to communicate up to 1.5KM, but from our test, even with line of sight, it is less than 150 meters if I remembered correctly.

Well, you may try your luck again with longer antenna, normally the antenna length should be half of the wavelength, 433MHz's wavelength is 69.28cm, commonly it is recommended to use 1/4 wavelength as the antenna, so 17.3cm!!

Another method is to use proper antenna with coaxial cable and attach to ANT1.
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Re: 433Mhz UART Module Arduino modification

Postby TanRunEn » Sat Mar 07, 2015 8:49 pm

Is this module suppose to work on standalone arduino like atmega328 on breadboard?
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Re: 433Mhz UART Module Arduino modification

Postby ober » Sun Mar 08, 2015 9:36 pm

We have yet to try it out, but it should work!
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