Author Topic: LoRa Library experiences / range  (Read 17693 times)

ColinR

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LoRa Library experiences / range
« on: September 02, 2015, 06:09:48 PM »
Hi all,

I'd like to know if any of you have spent time working with the LoRa Radiohead library. I want badly to switch to LoRa radios, but have heard that the library is lacking some pretty basic features, such as support for ACK, and does not include any encryption. This is pretty unfortunate.

Can you all share your stories, workaround, and any plans to bring the library up to the quality of the current RFM?

Cheers,
C
« Last Edit: December 01, 2015, 01:52:04 PM by Felix »
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Felix

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Re: LoRa Library experiences
« Reply #1 on: September 03, 2015, 09:28:31 AM »
Hi Colin,
Just to share my current thoughts publicly ... I have made basic changes to the RadioHead LoRa library (RFM95 branch under it) to make it compile and run on Moteinos and MoteinoMEGAs with LoRa radios (RFM95 stocked at LowPowerLab, but this should work with any RFM92-98 with proper frequency adjustments). Note that RFM92-98 radios are the same thing, except the differences are in frequency not in anything else, they are all 20dBm (100mW) output power.
So the RF95_client and RF95_server examples is what I use to test the MoteinoLR and MoteinoMEGA-LoRa units. From my little interaction with RadioHead it looks like there are the following options, quoting from the library page:

Quote
The following Mangers are provided:

RHDatagram Addressed, unreliable variable length messages, with optional broadcast facilities.
RHReliableDatagram Addressed, reliable, retransmitted, acknowledged variable length messages.
RHRouter Multi-hop delivery from source node to destination node via 0 or more intermediate nodes, with manual routing.
RHMesh Multi-hop delivery with automatic route discovery and rediscovery.

So that would include "ACKs", please see RadioHead for more info on this. I hope to have more time in the near future to play more with this as well.

ColinR

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Re: LoRa Library experiences
« Reply #2 on: September 03, 2015, 01:38:14 PM »
Mesh, you say. I will have to dig more into this when mine shown up. Thanks for sharing.

Colin
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gpsklaus

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Re: LoRa Library experiences
« Reply #3 on: September 16, 2015, 06:32:53 AM »
Hi All,
with a lot of success i am already using LoRa RFM98W for transmitting GPS navigation data.
Received data can be seen on OLED display and also are available serially for external use.
Used sketches are based on software originally created by Stuart Robinson, UK.
His ideas can be found here: http://www.rcgroups.com/forums/showthread.php?t=2454546

See also my page ( still in preparation ): http://www.kh-gps.de/lora.htm
Future intension is using board MOTEINO LR.

Klaus

 

Felix

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Re: LoRa Library experiences
« Reply #4 on: September 16, 2015, 08:11:59 AM »
Klaus,
Thanks for your input, nice resources, is there a particular library you used or was it all in the sketches that you linked?

gpsklaus

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Re: LoRa Library experiences
« Reply #5 on: September 16, 2015, 08:53:16 AM »
Hi Felix,
i am using the libraries as provided by Stuart Robinson via Dropbox: https://goo.gl/TYsFBf

Schematics on my page:  http://www.kh-gps.de/lora.htm are showing interconnection between processor and LoRa chip. So, after adding two additional wires, this also should run when using MOTEINO LR boards.

Klaus
« Last Edit: September 16, 2015, 08:57:23 AM by gpsklaus »

ColinR

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Re: LoRa Library experiences
« Reply #6 on: September 16, 2015, 02:44:59 PM »
Felix,

Have you yet looked at this library?

Still no encryption. What's the best way to build this in?

C
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Felix

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Re: LoRa Library experiences
« Reply #7 on: September 17, 2015, 10:48:31 AM »
I have not. It's not a library, just a sketch.
By virtue of the modulation scheme, the encryption is basically almost not needed. If you really want to, you can implement a soft encryption the same way it's done in the RFM12B library.

ColinR

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Re: LoRa Library experiences
« Reply #8 on: September 21, 2015, 12:07:58 PM »
How about a dedicated encryption engine, such as the ATAES132A? They're about a buck.

C
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Felix

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Re: LoRa Library experiences
« Reply #9 on: September 21, 2015, 12:17:07 PM »
It could work, if you go that route I'd get AES256.

ColinR

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Re: LoRa Library experiences
« Reply #10 on: September 21, 2015, 12:29:28 PM »
I don't see an Atmel with greater than 128. Could probably just get an extra 328 and drop a library/sketch on there.

C
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WhiteHare

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Re: LoRa Library experiences
« Reply #11 on: December 01, 2015, 11:16:56 AM »
Hi Felix,
i am using the libraries as provided by Stuart Robinson via Dropbox: https://goo.gl/TYsFBf

Schematics on my page:  http://www.kh-gps.de/lora.htm are showing interconnection between processor and LoRa chip. So, after adding two additional wires, this also should run when using MOTEINO LR boards.

Klaus

Hi Klaus,

I visited your web page.  Very nice work!  If I am understanding your results correctly, you achieved a transmission distance of 2,500 meters.  Is that correct? 

A few questions:
1.  What radio settings did you use (e.g. Tx power, bitrate, bandwidth, etc.) to achieve that range? 
2.  At what elevation was your LoRa transmitter?  It appears that your LoRa receiver was at the height of your car dashboard, is that correct?  What I'd really like to know is: what was the difference between the elevation of the Transmitter and the elevation of the Receiver [i.e. (Height of Transmitter) - (Height of Receiver)]?
3.  At the distance of 2,500 meters, about what percentage of packets were getting lost?

WhiteHare

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Re: LoRa Library experiences
« Reply #12 on: December 01, 2015, 01:03:54 PM »
I soldered the headers and the provided antenna wire onto some Moteino LR's this morning and loaded the example client and server sketches onto a couple of them (actually, the client came preloaded on the Moteino LR, which makes verifying new Monteino LR's easy).  Applying power to Vin and without making any other modifications, I put the LoRa server in a second story window and then walked around the neighborhood just now, simply looking at the blinking light on the LoRa client to ascertain whether there was a viable roundtrip connection or not.  With only that crude method, I'd estimate I  was getting viable communication within a 500+ foot radius using whatever the defaults are in Felix's adapted Radiohead RF95 sketches.

As far as fresh out of the box experiences go, I'd rate this one as very satisfying.   :)

Subjectively, this setup seemed to send more roundtrip packets successfully when standing still than when moving, even within my own house and even then at fairly short distances.  (i.e. it seems to do better when everything is stationary).  Call it an impression.  I don't have hard data that would prove it to a skeptic.
« Last Edit: December 01, 2015, 01:07:09 PM by WhiteHare »

joffers

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Re: LoRa Library experiences
« Reply #13 on: December 01, 2015, 01:32:01 PM »
I had a similar great out of the box experience using Moteino and RadioHead. I was easily able to verify multiple RadioHead client/server examples. Yesterday I put one of the MoteinoMegaLR in the car and drove around the neighborhood. Mind you the radio was in the car, sometime windows open/sometimes not.  With the server in my living room near a window (about 9 ft off the ground) I was able to get pretty consistent results at 640 meters through a heavy urban and wooded area (Seattle). After driving into a deep valley and then up a hill I got again consistent results at 1280 meters while just holding the radio near the open car window.  I was so excited I forgot to print out the signal strength but I'll be doing more tests and will post them here :)

WhiteHare

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Re: LoRa Library experiences / range
« Reply #14 on: December 05, 2015, 12:28:29 PM »
From reading the .h file, all the default settings are for medium range.  It offers two prebuilt settings for long range, though i'm not savvy enough yet to know which of the two would be the absolute longest range.  Is it the 32khz one?

The good news for indoor use is that the tx power can be adjusted across the full range (unlike the rfm69).  Also, the rx current is less.  I'll need to try the short range settings to get a better feel for how the two compare in real life though.