my family has a garden and a house about two hours away from home. I would like to be able to check from a distance if everything is fine. Some temperature sensors, maybe water sensors, cameras. Also beehive surveillance and perhaps the ability to water some plants remotely or deter raccoons.
(I already have sensors and cameras.)
First of all I will need an internet connection. There is no DSL in the garden, so I thought of an LTE router. Since I don't live there, the system has to be stable enough to run for several weeks.
Now I wonder what devices I should look for:
TP-Link WR200?
Raspi 4 with USB-LTE-modem (which one?)
MikroTik RBM33G - RouterBoard (which MiniPCIe-LTE-card?)
Some Wlan Router with USB-port and USB-LTE-modem?
It is not supported yet by OpenWRT but RouterOS is not that bad. Since the router is based on the IPQ4019 platform, with some tinkering it can be supported.
Personally, I have switched to Alcatel HH71VM units since they can be purchased for cheap and have a micro usb serial port. That said, they are using the RealTek RTL8197FS-VE5 which is not officially supported yet. Still needs some love according to this post: Any plans for Realtek SOC support? - #22 by gaspare
I like the look of the GL-mifi device that @reinerotto mentioned. I was looking at that one when I was considering whether my parents in law needed a backup internet for when trees take down their wired network...
To address the issue @frollic mentioned, set up your device to use a wireguard tunnel to your home.
ARM is the way to go, your major issue is to find a modem that will either reconnect on its own or have a reasonable decent way of telling the user when link is down.
If you need reliable & stable you need to look for industrial routers.
Teltonika for example uses openwrt and it does not cost too much.
I have also tested ewon, rocksolid but pricey and no openwrt. The first one i used works now 8 years 24/7
I also tried turris omnia but my experience is that it is not reliable (LTE side) and zero support or LTE.
It even disconnects (probably sim card holder issue) at temp below zero. You will probably face this issue with all non industrial grade routers if the temperature at the remote location garden falls below zero.
Whichever device you will use, I suggest that you use surge protection for cables longer than 10 meters or your device will be fried after a short period.
For sensors and other operations you could buy a raspi or orange pi and connect it to the router
When you consider Teltonikas to be temp resistant, this is good to know. Used RUT955 myself, good device, so this is worth a serious look then. Only drawback: Official openwrt does not work on this ones RS485. However, direct connection of sensors can be done using USB-converter. No need for additional raspi etc.