A way to connect 2 AVRs

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reSpawn
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Posted by reSpawn: Sun. May 18, 2008 - 12:16 PM
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Hello, I'm searching for a wireless way to transmit data between two AVRs and I've found some devices which I think may do the job.

The first device I found at a local shop is this one:
RFM12B/868D Miniature transceiver RF -102/7dBm 868Mhz FSK SPI DIP
Manufacturer: HOPE MICROELECTRONICS
+ is incredibly cheap( 4.87 USD )
Here is a link with a description of it: http://www.hoperf.com/pro/RFM12B...
+ They say this one works at over 300 m, that's ok for my purpose.(I need at least 100 m)
- is harder to interface( at least for me).

And a second one:
RTX-MID-3V Transceiver RF -110dBm/10mW 433.92MHz AM
Manufacturer: AUREL
- is expensive ( 23.11 USD )
link: http://www.aurelwireless.com/sch...
? I couldn't see where they specify the maximum range this device works, but I guess it's ~100 m.
+ it's easy to interface, because it can be connected to AVR's USART.

The thing is don't know which one I should get because I guess they both work on controlling a RC Car(miniature car), that's why I'm asking here if someone had a previous experience with one of those, and can give me some suggestions( point me in the right direction ).

Thanks in advance.

Nicu reSpawn.

Tags:

AVR Microcontrollers, megaAVR and tinyAVR
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reSpawn
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Posted by reSpawn: Mon. May 19, 2008 - 07:21 PM
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damn it, I think i'm gonna get RFM12B/868D Miniature transceiver RF -102/7dBm 868Mhz FSK SPI DIP because I run my atmega at 5V

Nicu reSpawn.

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jgmdesign
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Posted by jgmdesign: Mon. May 19, 2008 - 09:30 PM
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I use linx technologies trancievers.

www.linx.com

Jim

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cybertron
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Posted by cybertron: Fri. Nov 14, 2008 - 11:30 AM
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reSpawn,

Did you already buy the RMF12B?

I'm planning to buy the same module and am wondering if you got it to work.

Did you already overcome the problem 5V / 3.3V? The SPI interface is 3.3V at the RFM12B and 5V at the mcu.

I think I'll solve that by putting a 4050B between them. Power the 4050B at 3.3V and let the mcu feed it with 5V. The 4050B can handle higher input signal than Vcc.

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reSpawn
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Posted by reSpawn: Thu. Nov 20, 2008 - 08:57 PM
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Hello,
sadly no, I have bought bluetooth instead.
But in the next coming days I will get a HM-R and HM-T (they don't have HM-TR at the local shop).
and regarding the 5V to 3.3V, I think you'll be fine with a resistor in series! (or a voltage divider).
BTW, you might want to check this out:
zenburn.net/~goroux/rfm12b/rfm12b_and_avr-%20quick_start.pdf

Nicu reSpawn.

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