This isn't really a dev/tech post, but I wanted to be public somewhere with the information because I found nothing in Google for a problem.
A company called Digoo (seems to be part of a larger thing, since their app has support for hundreds and hundreds of home automation IoT thingies) makes an alarm called the "DG-ZXG30".
From what I can tell, they make it in 2G&GSM versions, and also the one I had to buy, the 4G&GSM one. A prior version of this alarm was the DG-HOSA which is packaged a bit differently and isn't quite as featureful.
I'm in Germany and our 2/3G cell networks here are shutting down in 2021, and that leaves only the 4G option.
So the alarm works on 4G frequencies 850/900/1800/1900Mhz, 2.4 and 5Ghz wifi, and uses 433mhz wifi for accessories (door and window sensors, and PIR motion detection)
I was disappointed to note when I tried to use this with a partner SIM from my telekom provider that it didn't achieve a network connectivity. (wifi, sure, but no cellular)
After some debugging, it occurred to me that maybe the PIN entry on the SIM card wasn't working. The device prompts to "dial" when inserting a SIM after booting, and appears to accept the input but it didn't work.
I removed the SIM PIN using another device (tricky, the alarm wants a full-size sim, and all my spare phones want micro- or nano-SIM), I have a laptop which takes a full-size SIM card, and on Windows it's quite easy to remove a SIM PIN in the cellular "Advanced options" settings dialog.
Now, within moments the Digoo alarm has a really strong signal, and I can finally confirm it all works as hoped.
Interesting, too - it's using a separate modem. At some point I tore it apart to check, I really expected to find a rebranded low-end mobile phone SOC, and I suppose maybe this is, but it's right next to an ARM chip I couldn't adequately identify which has the right format to be a little, probably fairly capable SOC, indeed a GigaDevice ARM32-M3 at least, though I didn't look more deeply into the possible specs.
For under 80 Euro, this alarm is crazy cheap, with all the accessories it has, I'm really pleased with the purchase, now that I got it working.
Top comments (2)
Perhaps this is a silly question, but why 4G? Since it's your home couldn't you just use wifi, or is the signal too weak there (e.g. your garage is away from the house)?
I ask because I do a fair amount of IoT stuff and shorter range options like wifi/Bluetooth/zigbee/z-wave normally suffice.
It's for my garage which is 2km from my house.