I want to order a JeedNode (v4), but I cannot figure out how to specify the frequency. I want the 434 frequency that is receivable by the RFXCom receiver. In some of my research, I seem to have found that the frequency is software set-able. Is that correct?
RF 12 Frequency
(12 posts) (2 voices)-
Posted 16/03/2010 18:54:39
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The RFM12B units in the Jee Labs shop are optimized for 868 MHz (for the US: 915 Mhz, see http://www.moderndevice.com/ ).
While it is indeed possible to send at 433 Mhz, the power will be reduced - even with an antenna tuned for 433 MHz. This is due to the components on board of the RFM12B module. There is some more discussion about this at http://talk.jeelabs.net/topic/66 and http://talk.jeelabs.net/topic/110
See also http://talk.jeelabs.net/search.php?q=OOK+ASK - the RFM12B is made for sending FSK signals (i.e. "FM"), whereas the simpler sensors which RFXcom decodes use OOK (i.e. "AM").
Another option is to hook up a separate transmitter made for this frequency band, such as one of these:
http://www.conrad.nl/goto.php?artikel=190224
http://www.conrad.nl/goto.php?artikel=191511In that case, you don't specifically need a JeeNode of course. Unless you want a nice and shiny little blue-with-gold unit :)
Posted 16/03/2010 19:38:16 -
Well, now I have to do a little more research. Is it possible to put my order on hold? The order number is #1579.
I was let to believe from post on a list here in the US that the RFXcom would be able to receive the signals on the 433 MHz band.
Thank youPosted 16/03/2010 21:01:24 -
Sure - let me know when you want to cancel or proceed with the order.
As I understand it: RFXcom can only receive OOK-modulated signals (as sent by various sensors). The RF12 driver can make the RFM12B send such signals, but unless it's a 433 MHz unit (which I don't have), the signal won't be as strong.
(feel free to pass this info on to the original poster you refer to, or to draw his attention to this discussion)
Posted 16/03/2010 22:06:01 -
I still have not decided what to do. If the RFXCom cannot interpret the data then that option is out. So then two jeedNode (v$) could be used one as a transmitter and one as a receiver. Am I correct. The method of data transmission is immaterial, since i provide the data to the atmega as input and another atmega interprets it and sends it to my home automaton system.
As an aside, my Home automation system XTension (see http://www.shed.com) can receive the Oregon Scientific sensors such as temperature and humidity as well as the X-10 security door, widow and motion sensors. Does that make a difference to your assessment?
Do you know where I can get a 433 MHz unit? Is it just a plug in device from Hope RF? Futurelec seem to have the 433 Mhz unit and are they compatible with the JeeNode?Posted 17/03/2010 14:35:53 -
I'm a little confused w.r.t. your requirements...
433 MHz OOK receivers in the US? Probably SparkFun.
Yep, Futurlec RFM12B seems to be what you want, but again - OOK reception is not feasible with RFM12B's, only transmission.
If all you want is to get from A to B with two JeeNodes, then there's no need to use 433 MHz, 915 MHz units are standard in the US, as available from www.moderndevice.com
Posted 17/03/2010 15:54:34 -
The euros are burning a hole in my pocket, hence the attempt to buy in The Netherlands.
Anyway, here is what I am trying to do. I have a electric current sensor that the Arduino reads and send the data ( I guess it is ASCIi) to the computer via the USB. The computer then interprets it and logs it. I do the same for a luminance sensor. I have ideas to do this for additional sensors. These sensors are dispersed throughout my house. Therefor I need a wireless path to communicate with the computer. The JeeNode seemed like a good way to do it and use my euros at the same time. Does this make sense?Posted 17/03/2010 16:27:09 -
Ok - thx for the explanation.
Sure, collecting data with JeeNodes is what I do all he time. Just keep in mind that in the US, you should use either 915 or 433 MHz - I don't think the 868 MHz band is allowed for ISM use in the US.
If you want, I'll change your order to 2 JeeNodes without RFM12B - and either refund the difference, or you can let me know what else you'd like to get for the €10 difference. Then you could get the RFM12B's at Modern Device or elsewhere.
Just let me know, and good luck with your project(s).
Posted 17/03/2010 17:08:37 -
My question about the RFXCom was just that I already have that working, so I could eliminate one JeeNode on one end.
Posted 17/03/2010 17:30:18 -
My answer is as before:
As I understand it: RFXcom can only receive OOK-modulated signals (as sent by various sensors). The RF12 driver can make the RFM12B send such signals, but unless it's a 433 MHz unit (which I don't have), the signal won't be as strong.
Posted 17/03/2010 19:28:56 -
Ok, Jean-Claude, I'll take the two JeeNode (v4) (without RF) and a PressurePlug. Let me know via my email how to pay you for what I may still owe you. I'll order the RF here in the USA. Looking forward to experimenting.
Posted 18/03/2010 14:03:24 -
Sent, thanks.
Posted 18/03/2010 14:19:58