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All things pertaining to wireless and RF links
By strefli3
#106200
Hello everyone,

I am cross posting this question from AVR Freaks:

http://www.avrfreaks.net/index.php?name ... ic&t=96303

I am currently attempting to transmit data between to atmega32s via 315MHz from the following modules form sparkfun:

RF Link Transmitter - 315MHz
sku: WRL-08945
http://www.sparkfun.com/commerce/produc ... ts_id=8945

RF Link 4800bps Receiver - 315MHz
sku: WRL-08947
http://www.sparkfun.com/commerce/produc ... ts_id=8947

I have followed the tutorial referenced from sparkfun: http://winavr.scienceprog.com/example-a ... llers.html

I have verified that I have communication by touching the TX and RX pins, ie, the code seems to be running fine. However, the same cannot be said over the wireless link. To help debug the problem I have attached the TX and RX to a scope. Referring to High.jpg one can see RX as the top trace and TX as the bottom trace. Notice that RX is between ~4.75V and 5V, the shape of the trace suggests that transmission is present. It appears to me that if RX went low then I would be all set. The second plot, Low.jpg is just that, I have connected the RX and TX and I have communication.

I have done an extensive search on this subject but all the discussions I have came across are a little bit to vague. I am not sure if I need to send more "startup bits" or move to Manchester encoding or maybe something completely different. A couple of hints should get me started.

Thank you for your time,

-P
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By languer
#106234
Take a look at this thread. The RX module used for the post you reference (Running TX433 and RX433 RF modules with AVR microcontrollers) is similar to the WRL-08948, not the WRL-08947. Even though the WRL-08948 RX module has slightly lower performance than the WRL-08947, it is more forgiving and will probably work for you. Looking at the posts and comments on the WRL-08947, my guess would be that the TX module was not re-aligned by the manufacturer after the newer RX module was introduced. My recommendation would be to try WRL-08948 RX module.