Best way to connect to RPi at a long range?

[0phoi5]

Hi all,

A relative is a farmer and has a Raspberry Pi set up in a field, that monitors various stuff.

He would like to be able to connect to the RPi from the farmhouse, rather than travel down to the field just to get the data from it.

The distance is around 1.5 miles from farmhouse to RPi, with a fairly clear line-of-sight (a few sparse trees and potentially the very edge of someone's house).

What would be the best way to connect to it?

I've considered using a 3G dongle on the RPi and using SSH over the net, or bridging the 2 with a Yagi on each end (pointed at each other). But which would be best, or something else? I have to consider power requirements as well, as at the moment the RPi doesn't take much (it's battery can last a good few days), but I don't want connecting extra equipment to it to make it last much less.

*edit* I also found this; https://www.cooking-hacks.com/sx1272-lora-shield-for-raspberry-pi-868-mhz    Any good?

Also, I'm techie-minded, but haven't connected to an RPi using any of these methods before, so any links to tutorials or instructions on how one would go about this would be great.

 

Thank you for your time.

Edited June 21, 2016 by haze1434

[barry99705]

That lora shield is pretty cool(i've not used one but 868 and 900mhz travels better).  Would probably work if you're just using a terminal.  Range is still iffy.  Would still need directionals.

Edited June 21, 2016 by barry99705

[metatron]

I've played with the lora stuff on 433MHz, range was fairly good, five-ish miles in a village environment. Towns and cities gets about a mile from experimentation, on a farm I'd not see there being an issue, other then data rates, but if you are just monitoring things like UV, PH levels, wind speeds, temperatures, barometric pressure, humidity, basic shit like that, or using it to trigger relays, then 433MHz is great.

 

[0phoi5]

15 hours ago, metatron said:

I've played with the lora stuff on 433MHz, range was fairly good, five-ish miles in a village environment. Towns and cities gets about a mile from experimentation, on a farm I'd not see there being an issue, other then data rates, but if you are just monitoring things like UV, PH levels, wind speeds, temperatures, barometric pressure, humidity, basic shit like that, or using it to trigger relays, then 433MHz is great.

 

That does sound perfect, that's basically what the RPi is doing yes.

I've done some general research on this LoRa stuff, but I don't quite understand how one would connect to an RPi and get a command line with it? Is that possible?

[metatron]

13 minutes ago, haze1434 said:

That does sound perfect, that's basically what the RPi is doing yes.

I've done some general research on this LoRa stuff, but I don't quite understand how one would connect to an RPi and get a command line with it? Is that possible?

You can use these as stand alone units or feed/receive serial from a rPi, although I don't buy from Adafruit, as I just normally get stuff from China and not pay the US shipping and other additions. If you go with a Adafruit product you do get support and code examples 

https://learn.adafruit.com/adafruit-feather-32u4-radio-with-lora-radio-module/using-the-radio

[0phoi5]

This looks great;

http://tutorials-raspberrypi.com/let-raspberry-pis-communicate-with-each-other-per-433mhz-wireless-signals/

But those little units don't look like they'd communicate very far.

[metatron]

You might want to go for Chinese ones, the ones I got from AliExpress were $4 each and had no issues range wise. Realistically if you just use a bare wire like they do you aren't going to get the best range,  you can get cheap Chinese 70CM band antennas which cover rx/tx on 420 to 450 MHz.  

 

Edited June 22, 2016 by metatron
odd formatting

[0phoi5]

Apologies for the multiple questions.

I was wondering if 2 of these, coupled with these instructions, would be a good thing to try out?

*edit* Would this allow enough bits to be transmitted to get a command prompt on the RPi, and use it?

Edited June 23, 2016 by haze1434

[metatron]

They look like regular 433MHz modules, the likes you would use for lots of tasks, like weather stations.

http://www.seeedstudio.com/wiki/2KM_Long_Range_RF_link_kits_w/_encoder_and_decoder

I'm fairly sure they aren't bidirectional, like http://www.aliexpress.com/store/product/Long-distance-LoRa-SX1276-SX1278-RF-wireless-module-DRF1278F/1396782_2021201457.html 

http://www.aliexpress.com/item/Long-distance-wireless-433-868-915Mhz-Lora-and-GPS-Expansion-Board-for-Raspberry-Pi/32672385182.html?spm=2114.01010208.3.2.3RzDoD&ws_ab_test=searchweb201556_10,searchweb201602_5_10017_405_404_507,searchweb201603_1&btsid=9ee166ce-9420-4189-a951-7958fc8d64af is kind of cool

 

Edited June 23, 2016 by metatron