DIY 3G/4G LTE Cellular Security System With Smartphone monitoring (long)


Old 03-18-17, 10:44 AM
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DIY 3G/4G LTE Cellular Security System With Smartphone monitoring (long)

Hello everyone, this is my first post here.

I have been messing around with a 3G/4G cellular security setup and wanted to post this for discussion as I have scoured the web and seen nothing that is relevant to using ONLY cellular data to communicate to your smartphone for a security system (most people dismiss the idea).

We are going to set up a cellular DIY security system and use our smartphone to monitor the alarm status, view videos, images etc... (I see a moderator sticky post above "I want my alarm to call my cell phone..." says that phones can't be used for this but that has to be out of date by now?)

Why use a Cellular System?

If you have a remote fishing cabin, camper, or vacation house, using cellular may be the only option. In my case I just rented a warehouse and wanted to monitor it for security. But I did not want to pay for a formal hookup such as cable, fiber or DSL.

So I am using a "mobile hotspot", a tiny device about the size of a PC mouse that connects to a 3G/4G LTE system and provides a wifi hotspot so you can use any wifi enabled device to access the internet via a cellular data only plan. You pay only for data, there is no voice aspect

Here are some examples of devices that may work-

T mobile - Alcatel linkzone (I have an older ZTE unit)
Verizon - various JetPacks (mobile hotspot) and USB modems
AT&T mobile hotspot - Velocity and Unite

These devices are certainly not promoted by the carriers, they would rather sell a full on voice/data plan, and can be tricky to find on their web sites. But I was able to get 6GB/mo from T-Mobile for about $30 per month.


I have discovered that mobile hotspots don't give a real IP address, the carrier has the ip address and the one exposed to you is one step removed. This is the double IP address problem (probably not technically correct). This means you cannot open a port on the cellular modem/hotspot to "suck" video from your IP address remotely, the most common way of accessing video remotely. You will need a workaround, but it can be done!

-Data caps- no problem, we will set it up to only send video or use data when requested or when motion or sound or other another event is detected. I do not see data caps as a disadvantage for this application.

-Cellular modems like these typically have no ethernet port, so to connect to the internet you have to use WIFI or USB. Or workaround.


-The mobile hotspot is most likely battery powered, so cannot be interrupted by power outages. Mine can last a whole weekend unplugged.

-The mobile hotspot is tiny and can be well hidden.

The Set Up

#1- Old Cell phone.

The easiest method is to use an old cell phone and an app like Warden Cam (available on Google Play). Install this app on the old cell phone and select "camera" so that it acts as a wifi camera and sends data to the hotspot. You can configure the cell phone's camera to send alerts when motion is detected. It can upload video and stills to your google drive or dropbox when events are detected.

You will be using your current smartphone as the remote monitoring unit. Install Warden cam on your cellphone and select "Viewer" and you will receive alerts when motion is detected along with access to the video clips.

I did use Warden cam, it avoids the "double IP address" problem because the camera and viewer log into your google account causing the camera to "send" video rather than trying to open a port and suck the video out. You can get nice clear video and sound anytime remotely with uploads to the cloud. Only problem- no IR night vision.

#2- IP Camera.

You can use a wireless IP camera. I have a 7 year old Foscam (perhaps try the newer Foscam FI9831PB 960P HD Indoor Wireless IP Security Camera). With the latest firmware the ancient Foscam can monitor for motion and sound. It has IR LEDs for night-time surveillance and you can put in your google/yahoo/ other email address so that it can send you alerts (with 6 images) via email to your smartphone when events are detected. There are thresholds for motion and sound and the email indicates if sound or motion caused the alert. Super cool.

Since your cellular hotspot has no ethernet port you will need a network switch connected to your PC and to the camera to set the IP address and WiFi network login info on the Camera. This is a pain but necessary to get the camera configured on your WiFi network. Once it is on the WiFi network you can toss away the switches and cables. It will work stand-alone. If you are in the building you can use the full functionality of the IP camera wirelessly.

The disadvantage is that you cannot control the IP camera (pan tilt zoom or change settings) once you are distant and cannot stream live video from the IP camera as it uses the port opening method to allow remote users to connect and control (even using a DNS service like will not work). However it has no problems sending data itself to you once it is set up and running.

#3- Network Security Systems.

There are some networking security systems but most require an ethernet hookup to your router. As the mobile hotspot has no ethernet connectivity you will work around this buy getting a cellular router or 3G/4G router.

example- TP-Link N150 Wireless 3G/4G Portable Router ($20-30)

The router will have a USB input to communicate with the mobile hotspot, and an ethernet port to communicate with networked devices. (Make sure the router is specifically designed to interface with a mobile cellular 3G/4G modem via USB!) This essentially provides ethernet capability to the mobile hotspot (wifi on the original device is also active simultaneously)- note that there is still the double IP address problem so that you cannot open a port for remote communication. I hooked up the TP Link to my T-Mobile hotspot via USB and it was plug and play- no problem!

I would think most networked security systems should work. I installed a:

Netgear Arlo Security System - 1 Wire-Free HD Camera, Indoor/Outdoor, Night Vision (VMS3130)

This has a battery powered camera and powered base unit. The base unit connects to the router by ethernet. The battery powered camera communicates to the base unit wirelessly. The whole thing is controlled by the Netgear Arlo app on your phone.

Works great out of the box, no special or unique steps required for setup. Disadvantage is that my version has no sound (I think other Arlo models do have sound). Other disadvantage is price- its a little pricey.

So using some or all these methods I can roam the world receiving alerts on my cell phone when events are detected in my warehouse, and the warehouse need not have access to a cable modem, DSL or other wired internet line.

Of course if you have a standard setup with wifi and a normal router, all this stuff can be done as well...and easier.
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Old 03-18-17, 03:46 PM
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A couple things..

First of all, this is wrong.
These devices are certainly not promoted by the carriers, they would rather sell a full on voice/data plan, and can be tricky to find on their web sites.
Voice and SMS are not the moneymakers. Most carriers don't even have metered voice/SMS anymore, they just give you unlimited. Hotspot-only plans are almost as expensive as voice/data plans, because all carriers are overpricing/overvaluing the data they sell you (under the guise of data being "more taxing on the network" - which is total bull).

Second, you can not tether a hotspot like the Jetpack or a smartphone to a router. Cellular routers only work with specific USB modems, and that modem must be compatible with the service you intend to use it with. The Jetpack requires its own drivers for USB tethering to a computer and can not be tethered to a router. The only way to do it is with a router capable of using a WiFi WAN (which the majority won't do out of the box, they require a custom firmware like DD-WRT) to connect to the hotspot's Wifi, and even then hotspots are very unreliable when it comes to 'continuous' connections.

I live in the middle of nowhere and I can still get a 10/3Mbps internet connection for $25 a month. If it's your only option? Sure, you're stuck with cellular. But as an "alternative" because you "did not want to pay for a formal hookup such as cable, fiber or DSL", it's kind of silly because a wired connection is going to be more reliable and more flexible as far as what you can do with it, and it requires a lot less kludging things together.
Old 03-19-17, 10:09 AM
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The Sticky hasn't been updated in some time, primarily because I've not had time to mess with them; but also because the information contained therein really hasn't changed in any fundamental way.

Intrusion alarms still are made for connection to central stations receivers; UL still will not certify any of the self monitoring schemes. Systems that do have a means of using mobile phones to access and control intrusion alarm system still have to work through some sort of third-party interface.

And none of them really work well with the common land-line replacement systems available to the mass market.

It's not that mobile phones _can't_ be used for alarm connection; it's that the information and utility from such a connection is limited, without additional service and/or hardware involved.

Also, you are conflating intrusion alarm and video, which are two very different things (despite mass marketing misinformation).
Old 03-19-17, 01:13 PM
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My warehouse is in a business park so the only options for a wired data hookup are commercial business plans- which are far more expensive in that location than say Uverse or time warner for residential purposes (but they would be insanely fast w/ very high limits). The mobile plan was far cheaper than the wired plans available, so even though residential plans in nowhereville are cheap there are other factors that sometimes come into play.

Correct on "tethering" a smartphone (in hotspot mode) to a router- it cannot be done without the custom firmware.

I hear you on the alarm/monitoring difference- newbie mistake!

I also may be wrong on port forwarding, my modem does allow for it and I did try it for hours and hours unsuccessfully... but I found a post somewhere where a guy said he got it working so I am going to try more next week...
Old 03-19-17, 02:10 PM
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I understand now about your ISP issue. Didn't think about that aspect.

As far as your inbound connectivity, you have what's called a "Double NAT" situation. All routers do something called NAT - Network Address Translation. This is what allows your multiple LAN computers to each have a "private" internal IP and share the same external WAN (public) IP. The problem you're having is that the router is doing NAT, and the hotspot is ALSO doing NAT. This means your portable router gets a private IP address on the WAN side, and because of this requests that come in from the hotspot to anything on the LAN side of the portable router are thrown out by the firewall (since "private" IPs are not routable over the internet, and the firewall identifies them as bogus).

The easiest way to deal with this is to put the WAN IP of the second router in the first router's "DMZ".. However I don't think that's a possibility on a hotspot. Another way is to put the router into switch or bridge mode - essentially turning it into a switch instead of a router - this puts the responsibility for DHCP and routing on the hotspot. And then there's port forwarding. This is the most cumbersome route, because it requires every port used to be properly configured on both routers - but it may be your only option.

Last edited by taz420; 03-19-17 at 03:36 PM.
Old 03-19-17, 03:19 PM
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Right, double NAT! I researched this before and it seemed unresolveable for port fwding but then saw someone claim to get things working.
Old 03-19-17, 03:32 PM
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It can be done, it's just a pain in the ass, because it requires identifying all of the ports you need and which protocols they use, and then properly programming them into both routers in the correct manner. The second router also needs to be set for a static IP to ensure a reset doesn't cause the router to grab a different IP and break the forwarding setup. Much easier to set the router to switch/bridge mode (might require DD-WRT, I'm not familiar with TP-Link's firmware if it contains that option) and let the first router handle everything for this setup.
Old 03-23-17, 09:54 PM
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I set up something similar for my home alarm system, I have an envisalink with a pc1832 and some ip cameras. I wanted to be able to keep monitoring my alarm and cameras even when the main internet connection was down for whatever reason so what I did is to set up a second router with multiwan using an USB 3G modem so when the main internet connection goes down the 3G connection kicks in and then check for the main to comeback and it will go back at it.

In your case you can do what I did, get a cheap wireless router ( I use a linksys e3200 with USB port) load tomato firmware in it, get an USB 3G modem, this way the router will get the public ip assigned on the WAN side from the 3G modem and assign private ips to what ever is connected wired/ wireless to it. This will avoid the double nat, you will be able to do port forwarding, you can use ddns to monitor your wan ip and you get other benefit of a conventional wireless router.

That is what I would do

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