Author Topic: Which transceiver for home automation?  (Read 1566 times)

florint

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Which transceiver for home automation?
« on: July 19, 2017, 02:36:02 AM »
Hello all,

I am having difficulties in trying to select a transceiver for my Moteino order. I see many options on the order page. Which one is "better" for home automation? I understand LoRA has the lowest power consumption so it's great for nodes that run on batteries but what about the range? Which transceiver has better penetration through the house? Less interference with cordless phones, Wifi, microwave, etc? Also, are there any legal issues for broadcasting RF signals? Do I need a license (for the transmitters)? I tried to find out what frequencies are allowed in my city but I couldn't find any relevant information.

Thanks in advance!

F.

Felix

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Re: Which transceiver for home automation?
« Reply #1 on: July 19, 2017, 09:47:18 AM »
Any RFM69 will be great.
915mhz has the smaller antenna.
I would recommend RFM69_HCW_915mhz if that ISM band is open in your country.

ChemE

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Re: Which transceiver for home automation?
« Reply #2 on: July 19, 2017, 10:59:51 AM »
As long as your Tx duty cycle is less than 1% you will be compliant with FCC rules in the US.  Not sure about other countries.  A broadcast takes just a few ms so as long as you are not sending multiple times per second, nothing to worry about at all.

florint

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Re: Which transceiver for home automation?
« Reply #3 on: July 19, 2017, 03:34:16 PM »
I'm in US. Is there a website that specifies which bands are OK to use? In which ways is RFM69 better than LoRA?

Cheers,

F.

Felix

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Re: Which transceiver for home automation?
« Reply #4 on: July 19, 2017, 04:13:32 PM »
Just get RFM69_HCW_915mhz, you won't regret it. The RFM69 lib is very easy to use with many examples to start from.
LoRa has some advantages over regular FSK (more immune to noise) but IMO LoRa is more difficult to use and understand for a beginner. Also more expensive and overall not lower power due to the very low bitrates.

ChemE

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Re: Which transceiver for home automation?
« Reply #5 on: July 19, 2017, 05:14:43 PM »
With very little effort at all you can get the RFM69HCW that Felix is recommending to blast out small payloads at 300kbps that can be heard over a mile away.  LoRas use a lower bit rate and so have longer transmissions which use more power as a result.  I elected to use to RFM69CW because I don't need my broadcasts to be heard from a mile.  My lot is 50'x200' here near downtown so I can use much lower broadcast powers and Tx currents and still get messages across no problem.

john4444

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Re: Which transceiver for home automation?
« Reply #6 on: July 22, 2017, 11:55:50 AM »
Florint, ChemE makes a good point about the RFM69W & RFM69CW 13dBm transcievers.
Myself, I use multiple Moteinos w/ RFM69CW for my pool control.
I don't have to worry about running on batteries but extra transmit power does not help when you can receive without issues. I'm in a residential neighborhood with a somewhat noisy power line in the back yard. Yet, even with the background RF noise, I see good signal levels inside the house from the back yard (over 100-ft away).
As a licensed radio operator, I'm for using as little RF power for as short a time as possible in order to reduce the possibility of interference to others.
If everyone uses the lowest power/time usable then everyone experiences the least interference.
However, if one person transmits at high power for long times then everyone experiences interference.
Along the same line, using TomWS/Felix's ATC will maintain reliable signals at reasonably low transmit power (and supply current) even when background noise changes.
John AE5HQ

HeneryH

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Re: Which transceiver for home automation?
« Reply #7 on: September 23, 2017, 10:36:21 AM »
I don't know why, but a couple of years ago when I started this hobby/project I purchased 433 transceivers. 

What might I be compromising on with respect to 915?

If I were to install a new project location, using 433 would have the benefit of sharing spare parts with my first location.

Kilo95

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Re: Which transceiver for home automation?
« Reply #8 on: September 23, 2017, 11:01:58 AM »
Theoretically you’d compromise longer distance. My 915mhz setup works fine at my home. I have nodes all over the house. It works perfectly fine with a half wavelength antenna. It also worked fine with quarter wave antennas

AdiOltean

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Re: Which transceiver for home automation?
« Reply #9 on: October 24, 2017, 03:04:54 PM »
Hi all,

A few quick q. Comparing the datasheets of RFM69 (non-LoRa) and RFM95/RF96 (LoRa) it appears that LoRa has about the same bitrate (300 kbps) and slightly lower power consumption in active mode. Where RFM69 wins is in idle mode (1.25 mA vs. 1.6 mA for LoRa) but I'd argue you don't want that mode to be enabled all the time, instead you would stay in deep sleep mode most of the time. So it looks like the LoRa is more power efficient overall? Add to that the link budget of 168 dB which is nothing short of amazing.

The other question I have is around the RFM69 - would it cross several walls with max amplification? (say the sensor is on the other side of a large building). Don't have experience with RFM69 (only worked so far with LoRa which seems to work with even 20 dB below the noise floor)

Thanks, Adi