RF communication with AVRs?

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Hi - I was just wondering, what have people here done with giving AVRs RF communication abilities? I am currently working on a fairly basic system using some simple Laipac RF transmitters and receivers and Holtek encoders and decoders to remotely turn on/off the runway lights to my house.

It got me thinking though - what kinds of rf communication are fairly easy to implement with AVRs? I mean one could certainly use the Laipac and Holtek parts that I used to give an AVR 4 bit communication (the Holtek chips only send 4 bits at a time) - but also I would think that one could use an AVR to do the encoding and decoding, and skip the Holtek devices altogether.

So - what RF solutions have you all used? And has anyone coded a encoder/decoder for an AVR? And has anybody implemented a more complicated RF protocol - such as bluetooth or zigbee?

Thanks for your thoughts!

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I know there's a zigbee implemenation out there somewhere but it's on a relativly expensive daugter board. As far as simple AVR projects writting your own encoder/decoder really shouldn't be that difficult. Though I don't know anything about RF protocols, I'm sure there are rules you have to follow in order to make sure that data gets through.

-Curiosity may have killed the cat
-But that's why they have nine lives

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Look at this site: http://www.nvlsi.no
This manufactorer makes nice and easy to handle RF IC's. ie: nRF905. You can find lot's of documentation and app notes there, for RF design and protocol recommendation.

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Have You used those chips from Nordic Semiconductors? I assume it is not quite that easy to get a working RF module, since just the position of some of the parts can siginficantly change the RF behaviour.

So I would be interested in rather getting working RF modules, which "just" have to be interfaced. But maybe You can elaborate a bit more.

Frank

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nleahcim wrote:
Hi - I was just wondering, what have people here done with giving AVRs RF communication abilities? I am currently working on a fairly basic system using some simple Laipac RF transmitters and receivers and Holtek encoders and decoders to remotely turn on/off the runway lights to my house.

It got me thinking though - what kinds of rf communication are fairly easy to implement with AVRs? I mean one could certainly use the Laipac and Holtek parts that I used to give an AVR 4 bit communication (the Holtek chips only send 4 bits at a time) - but also I would think that one could use an AVR to do the encoding and decoding, and skip the Holtek devices altogether.

So - what RF solutions have you all used? And has anyone coded a encoder/decoder for an AVR? And has anybody implemented a more complicated RF protocol - such as bluetooth or zigbee?

Thanks for your thoughts!

I am not there yet either. I have read that for AM You have to use manchester encoding/decoding to make it work, which I am working on to implement.
Take a look at http://www.ft-fanpage.de/fernste.... Those guy has some plans and asm code in German though :-). Don't know if it works or not, but let's see.

If someone else has some material please keep us posted...

Frank

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I've ordered a pair of these but I have not tried them out yet. They look really great and are pretty cheap too! They use the nRF2401 chips from Nordic Semiconductor, so they take care of all the dirty work. Super neat little boards.

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Quote:
Have You used those chips from Nordic Semiconductors? I assume it is not quite that easy to get a working RF module, since just the position of some of the parts can siginficantly change the RF behaviour.

I have some nRF903 chips, but still not used in a circuit, because I have problems to find distributors for some of the external parts. I know RF design is tricky and critical, but since Nordic provides also reference design layouts and schematics it should be possible.

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Protocols like Bluetooth are normally implemented in a chip that does the protocol AND the RF side. Therefore your interface to these devices is via serial (RS232 etc) - there are bluetooth modules available that do all the hard work but they are still a little pricey (~USD$99). As for ZigBee I dare say the above comments still apply.

I think your easiest solution is to do your own protocol for the Laipac modules - a sniff around the web should unearth something - even if it's for a PIC the method is the same.

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Have a look a the AT86RF211 chip from ATMEL. It is also fairly easy to interface it to a AVR.

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erafrmu wrote:
Have You used those chips from Nordic Semiconductors? I assume it is not quite that easy to get a working RF module, since just the position of some of the parts can siginficantly change the RF behaviour.

So I would be interested in rather getting working RF modules, which "just" have to be interfaced. But maybe You can elaborate a bit more.

Frank


Try www.Elfa.se. Mark this number 7300460 and paste into the search field.
It's the nRF 401 Loop Kit. It consists of 6 modules with 3 different antenna loops.

Einar Sjaavik