Home security tech doesn't have to be large and obvious to make a difference. Some of my favorite security devices are tiny little gadgets hidden out of the way but still doing a world of good in my home. Plus, these small devices are often more affordable and less likely to come with annoying monthly subscriptions. 

You can outfit your home with security products like these without worrying about them getting in the way or taking too much work to set up. Plus, they're excellent for renters and can still keep away burglars or stop home damage. Here's what I'm talking about. 

Light bulb security camera

A light bulb security camera removes all the hassles of a camera installation for a smaller, simpler setup. You simply screw the light bulb into a standard light socket, and it runs a security camera along with a spotlight. You don't have to worry about power cables, placement, batteries or anything else. Plus, they're affordable.

The only catch is finding the right socket for these basic little cams, preferably an overhead light on a porch or entryway. You can find several picks on my best of list, starting with a $50 Symynelec bulb.

Hidden smart lock

Most smart locks are both large and feature-rich, which is great for some people but others don't want all that -- stuff, on their lock (or even have the room). I have a small, quiet solution: The Level Lock Plus (around $280). While expensive, it's an elegant little lock for someone who wants a lock that looks completely normal but houses some useful smart features, including the ability to unlock with the tap of an included key card, unlock through Bluetooth, or enable Apple Home Key access. All those are optional; it also just functions like a regular deadbolt with a key.

Standalone motion sensor

You don't need a whole security system to get a helpful sensor that can watch over one particular area in your home. Sensors like Eufy's for $30 are powerful devices with batteries that can last for years and with sensitivity settings to get awareness just right. They do require a pricey hub, though. Tapo's sensor is a more affordable option ($20) and with a hub that only costs $23.

Both sensors can activate phone alerts or sirens when motion is detected, like at an apartment entryway, toddler's room, garage and so on.

Standalone vibration sensor

Vibration sensors are a common addition to home security systems, where they're used to sense people tampering with safes or trying to break windows. But you can also find useful standalone versions that do the same thing for a fraction of the cost. This model from GE is $10 and quickly attaches to an important ground-floor window. Then it sounds a siren if it detects that the window is broken or pounded.

Smart smoke detector

You no doubt already have a few smoke detectors -- it's the law. But the smoke detectors placed during construction tend to be simple and annoying, chirpy devices (also, it's recommended to replace them every 10 years). But there are modern solutions that look just like your old smoke detectors, can be wired in if your state or country requires it, and add a couple of extra handy smart features.

The best choices right now are the Kidde/Ring collaboration detectors ($75) that work with the Ring app for free, and the Nest/First Alert detectors ($130) that work with Google Home. They both send you alerts on your phone wherever you are, and offer in-app battery warnings. They also make testing and management easy.

Smart radon detector

Radon is one of those annoying safety issues that's hard to examine, even if you know it's a problem in your geographical area. Testing and sending samples to labs for the radioactive gas is the sort of project that's easy to forget about. But there's an easier at-home option, a small device from AirThings called the Corentium Home 2 ($210).

This device is designed to measure the output of radon wherever you place it (like a basement). You can move it around your home to see where measurements are high and keep using it for years to come. Plus, there's no need to handle a sample kit or trust a lab for proper analysis -- or be surprised by unexpected lab fees. Just give the sensor a few hours to work, and you start seeing if radon is a problem in your home, which may need to be addressed with additional barriers. App connections are available for more info and control options.

Leak detector

A small leak detector fits in out-of-the-way places like under sinks, behind toilets and beside water heaters. There they wait for years to detect any spilled water on the floor, at which point they send out sirens and app alerts to let you know something is wrong. That's an easy and cheap solution to stop leaks before they cause serious water damage.