Hello,
Are there any modules for connecting wirelessly Arduinos in distances 18 km - 20 km LOS, in rural fields? I want to transfer data maximum 100-150 characters/sec. I need to be low power consumption, because I will use solar energy.
Any suggestion?
LoRa modules will work.
Check out this website, its open source, decentralized LoRa network. Maybe you don't need get your messages all the distance. I have not used it for a project myself but talked to them at some tradeshow a while ago.
This is a Arduino Uno board with 10 km range according the website.
Since range is a antenna, power budget thing there are linkely solutions to get more range. After all its already halve of what you want. Just need some directional antenna or a LoRa gateway from a community member in the middle.
The distance you need is at the outside edge of what LoRa will do, in ideal conditions. You would likely need to have a repeater node (or two) along the route.
The things network is a good idea in principle, but unless you're very lucky, there's unlikely to be a gateway in range of you, especially in a rural environment. For example, I looked at their map and the nearest ones to me are sixty kilometers away, mostly in cities.
The distance you need is at the outside edge of what LoRa will do, in ideal conditions.
The record line of sight range for LoRa transmissions is over 700 km, and it is easy to get 25 km.
all depends upon datarate/packet size....
alex5678:
Hello,Are there any modules for connecting wirelessly Arduinos in distances 18 km - 20 km LOS, in rural fields? I want to transfer data maximum 100-150 characters/sec. I need to be low power consumption, because I will use solar energy.
Any suggestion?
LoRa will cover the distance easily in good conditions.
But it depends entirely on the terain, hilly or flat and whats in the middle, hedges, trees, forests, how high the antennas are etc. There is no one answer.
Also depends on where in the World you are since there will be power, antenna and duty cycle restrictions.
150 characters a second may sound low, but if your transmit duty cycle limit is 1%, then you need to transmit at 15,000 characters a second to get the data through.
The Things Network has been mentioned, but its unsuited to your application as your limited by the fair access policy to 30 seconds of air time per day, it is a free service after all. And you need to be in an area of the World where gateways are common.
The distance record for LoRa is now 766km see here; 766km
jremington:
The record line of sight range for LoRa transmissions is over 700 km, and it is easy to get 25 km.
Good to know - all my knowledge of LoRa is theoretical. Does it need a special antenna or can you get that out of the box?
With LoRa no special antenna is required. A 1/4 wave whip, 1/2 wave dipole or just a short piece of wire can be very effective.
Can I build a mesh network with LoRA?
Mesh networks exist for LoRa and in any case, for a wireless network the exact method of transmission is immaterial.
We don't know your capabilities.
Yes, you can have mesh networking on top of LoRa. There seems to be some Arduino stuff available. Just Google LoRa Mesh.
The thingsnetwork I meantioned earlier is basically mesh network. No necessarily from simple nodes to nodes but the gateways build a mesh network. You can add your own gateways into the network and remove them at will. Since this is open source you can probably build your own solution without the fair use limitations. You still will have the duty cycle limit srnet mentioned.
alex5678:
Can I build a mesh network with LoRA?
Of course - see the RadioHead library on examples on this. A great library that is.
Mesh networking is a level above the transport layer, and as such independent of it. You can basically use any radio for mesh networking, in principle even a mix of different radios in the same network (if your software supports it).
LoRa modules are available at different frequencies - 433 MHz, 868 MHz, 915 MHz. Do check which frequency is available for your locality - likely 433 MHz, and one of the two higher frequencies. 433 MHz tends to have best range/penetration but requires bigger antennas and the frequency band is more crowded so there may be more interference.