I put Zigbee sensors on every door and window, and my smart home beats more expensive regular alarm systems

Published Oct 8, 2026, 2:30 PM EDT Richard is the PC Hardware Lead at XDA and has been covering the technology industry for almost two decades. He's been building PCs since young, and when not creating content, you can often find him inside a chassis somewhere. We had some fine people pop round our home to provide the sales pitch for a professionally fitted home alarm system. This would have involved a technician to drill into walls, wire up panels, and set the account up for a monthly subscription after paying a fair chunk of money for the installation. There's another route, which is what we took, consisting of a DIY kit from the likes of Ring. I got fed up with both choices, so I built my own alarm system using cheap Zigbee sensors, Home Assistant, and a free integration called Alarmo. The total cost came to less than what the initial kit price and first month subscription with Ring set us back by. I'm going to run through what I did, what I used, and why you may want to consider following suit to save a little and protect the home. Why I didn't want a traditional alarm system I wanted to keep costs down and retain control The primary issue I had with a professional system is it costs a small fortune to have the system installed, and there's an accompanying monthly fee for monitoring and other benefits. Now, I understand that in order to have local authorities notified of an issue at home, one needs to have a system professionally installed and monitored, which adds to the cost, but there's also a considerable markup on top of this. We were looking at quotes around $2,500 to kit the home, garage, and office out with protection. That's an incredible amount to spend on a single system, especially when the likes of Ring sell kits costing a fraction of that. You lose the direct link to local authorities, but I figured I can quickly give the police a ring if I spot someone breaking into my home. Plus, both I and my spouse usually work from home. The other issue is integration. Not all alarm systems are open, for obvious reasons. That rules out Home Assistant connectivity, which is something I rely on to power our entire smart home. Ring isn't officially supported as such, but the integration available through Home Assistant at least allows for sensor data to be added into the mix for automation, etc. The issue with Ring, Eufy, Arlo, and other brands is the reliance on the cloud. The Ring alarm station does have mobile and power backups, but this still relies on external services. We have to pay for it to be monitored and for specific Ring hardware to store more videos in the cloud. But again, we're relying on the cloud for security. I want to keep everything local, and so Alarmo through Home Assistant with some cheap sensors was used to plan out the perfect DIY system. What Home Assistant and Alarmo solve Creating a smart home alarm system If you've somehow avoided using Home Assistant to this day, it's the smart home platform for self-hosting your own hardware and services. It can run on just about anything, including an affordable Raspberry Pi single-board computer (SBC). If you already have a network-attached storage (NAS) or home server running, you're already there. Simply install it, fire it up, and install Alarmo. The platform itself can communicate with thousands of smart home devices, as well as a whole host of supported products through available integrations. Once everything has been added to Home Assistant, automations can be configured to run automatically. Everything runs locally without a single cloud dependence or subscription fee. There's also no vendor lock-in, meaning you can switch between and mix branded hardware. I have some devices from Sonoff, Innr, and other names that can all communicate and work together, routing everything through Home Assistant. Alarmo is one such integration that introduces many of the features alarm systems offer with keypads and central hubs. It can support modes for arming and disarming the house, schedules, geofencing, notifications, and even triggering sirens. One thing I decided on early before setting up the DIY alarm system was the network it would rely on. I opted for Zigbee. Zigbee changes the smart home game Wi-Fi is great for getting devices online. It's perfectly suited for laptops, phones, and other hardware, but it's not designed for handling hundreds of smart home devices. That's where Zigbee comes into play. Adding a few smart home products to the network can cause it to become more congested, which is why I wanted to move as many of them as possible to Zigbee, including all the alarm sensors. Zigbee is a low-power wireless protocol designed specifically for home automation. Switches, sensors, and locks are great for this protocol, though it's important to note that not all Wi-Fi devices support Zigbee and vice versa. And because Zigbee doesn't require as much power for devices to maintain connections, sensors attached to doors and windows can remain installed for years using a single pair of batteries. Then there's coverage, which can be complemented by powered Zigbee devices. Smart plugs are a great way to monitor power usage, offer remote control support, and even help broadcast the Zigbee network so your coverage extends beyond the reaches of the primary broadcaster. Sonoff powers the backend with sensors Good price, good quality I decided to stick with Sonoff for the sensors. I've had nothing but great experiences with other smart home products the brand has released. The Zigbee network is powered by Sonoff's USB dongle, and the company has just about every sensor your smart home would require. I picked up a pack of window and door sensors, a couple motion sensors, and a wall-mounted screen to act as the physical keypad, though it's entirely optional. Altogether, I'm looking at $185 for the full setup, though most of that is for the display at $129. A pack of four Zgibee door sensors can be bought for $40. A single motion sensor is around $16. Home Assistant is available for free and can be run on just about anything, though I'd recommend a dedicated device for the alarm system. Once everything is paired and added to Home Assistant, I'm now rocking my own alarm system with all data stored locally. No other company needs to know when I leave my home. I'm not reliant on some other service, nor do I need a specific brand to remain in business indefinitely. It does pass on responsibilities for the entire system to myself, but I enjoy monitoring and managing a home lab regardless, so there's no added workload. I save in the long run, get to make my home even smarter with full integration elsewhere, and everything is just as easy to use as a fully monitored system. Home Assistant OS Windows, macOS, Linux iOS compatible Yes Android compatible Yes This is all you need to create a bustling smart home and DIY alarm system.