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I have come across the various blogs which talks about cloning RF remote using cheap 434 MHz Tx/Rx and RCSwitch library.

I tried using RF 434 MHz ASK (https://www.sparkfun.com/products/10532) module with arduino, but the range I get it very less , just around 5-6 centimeters. Seems these RF 434 MHz modules are not stable. So I am planning to use now another RF Module which uses NRF905. Link - http://www.ebay.com/itm/2pcs-NRF905-wireless-module-PTR8000-wireless-transmission-433-486-915MHz-/270963407796

My query is can I use NFR905 based RF modules which is also 434 Mhz to clone any existing remote working on 434 MHz. Please help

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You can connect an external antenna to pin 8 on that module. Just use a piece of wire that is 17.3cm long. But since the range is that bad to start with, probably means it isn't tuned very well. I'd return it, or try fiddling with the pot at the back. Not sure why Sparkfun has these crap transceivers for sale. Transceivers without a crystal are very inaccurate in their frequency.

If you only need to transmit, I'd suggest this products: https://www.sparkfun.com/products/10534 . Those worked great for me, and are currently switching on the power sockets for my lights when it gets dark enough.

  • Thanks Gerben for your inputs and response. I will try out with a pot added at the back. Also, trying out with nRF905. This uses FSK instead of ASK. Is this module (nRF905) good for using in home automation or should I use ASK based RF modules only. – user3301213 Sep 24 '14 at 6:47
  • I really don't know the nRF905. It will probably work for home automation, but I'm not sure if it's the easiest to work with. E.g. the nRF24L01 I'm using for my home automation takes care of a lot of stuff, like addressing, data integrity, auto-ACK etc.. Using a raw data module like the module in the link I posted above, you'd have to implement all of that yourself. Glancing through the datasheet it look like the nRF905 does some of that too. The lower frequency may also help in getting a better range that the 2.4Ghz products out there. – Gerben Sep 24 '14 at 18:16
  • Thanks Gerban for your inputs and views, really appreciate. I am getting my nRF905 in couple of days. Will post the feedback once I use this. – user3301213 Sep 25 '14 at 8:33
  • +1 for the external antenna suggestion and the comment about the crystal (nowadays I always use 434Mhz with crystal). NRF24L01 is 2.4Ghz and will probably not suite for cloning an existing 434 RF remote. Also, the Sparkfun's product is a receiver, not a transceiver. – Omer Jan 20 '15 at 23:43
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can I use NFR905 based RF modules which is also 434 Mhz to clone any existing remote working on 434 MHz.

The answer is, inevitably, no, you cannot. Each such remote controlled device might have a different digital modulation scheme. Best if you could focus on one specific product and adjust your design to fit it.

Note that the two products you are referring to are both 433Mhz but differ by many other parameters, such as:

  • Supply voltage (5v vs 1.9v-3.6v)
  • Interface (single digital output vs SPI)
  • Capabilities (receiver vs transceiver),
  • Presence of a crystal
  • Power consumption
  • Price

This might affect your final design as well, and should be taken into consideration.

For example, from my experience, if you will shrink your project into a ATtiny85 at some stage, you might not have enough I/O pins to satisfy the NRF905, but enough for the Sparkfun's product (or a similar one).

but the range I get it very less , just around 5-6 centimeters.

The maximum range I got with the Sparkfun's module using a half-wave antenna (34cm) was ~40 meters inside a building and about 80 meters in open air. My testings with quarter-wave length was about ~30 meters inside a building.

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