I love smart tech: Between smart cameras, sensors, and robots and every kind, these machines save time and effort. However, they're often expensive, which makes shopping holidays the perfect time to invest in this technology. This Black Friday, some of my favorite smart tech devices that I tested this year are on sale, so if you've been thinking about picking up a robot lawnmower or smart security camera system, now's the time.Best robot lawnmowers Credit: Amanda Blum Having now tested a number of lawn-mowing robots, the ease and reliability of the Luba 2 makes it my hands-down favorite. (Read my full review here.) Full of features from video monitoring to GPS location if removed from the yard, the Luba even has lawn-printing capabilities now. (I was underwhelmed by this, but did print a bunch of stars on the lawn for the Fourth of July.) The only reason to choose a different mower is if your lawn is too smallor has a lot of obstacles to mow around. The Luba 2 is rugged and will handle everything from a medium-sized yard to a field with ease. The bots come in different capacities, each with their own discount for Prime Day.LUBA 2 AWD 3000 (up to .75 yards): Regularly $2,499, now $2,149LUBA 2 AWD 3000 (up to 1.25 yards): Regularly $2,899, now $2,249LUBA 2 AWD 3000 (up to 2.5 yards): Regularly $4,099, now $3,649If your lawn is smaller, you might consider the Segway Navimow. (Read my full review here.) The distinction I make between the Luba 2 and the Navimow is that the Luba is really rugged, but lacks the gracefulness to turn on a dime or tightly navigate around obstacles. For smaller yards, the Navimow is a great option, and it's incredibly reliable. It does not enjoy a dip in the yard or a hill, so you'll want to ensure the landscape is decently flat, but it handles an incline without a problem. Credit: Amanda Blum Navimow i105N: regularly $999, now $799Best outdoor security camera I'm not saying you should hang your string lights off them, but you can. Credit: Amanda Blum There are lots of good outdoor security cameras, but whenever Im done testing others, I put my Eufy Solocams back up. Theres lots to like, including the extraordinary range of vision that comes from the spherical pan-and-tilt that allows you to rotate the camera almost 360 degrees. There are actually two cameras in eachone for a macroview and one for a microview. The microview is spectacular for detail: I can actually get a detailed look at individual plants in my yard while Im away. I love that you dont need a monthly plan if you get a Eufy hub for storing clips locally, and that the live view comes up reliably each time with minimal wait time. The two cameras on sale are the hardwired floodlightsthe S330 and E340. I have both up as we speak, but also be sure to look at the solar powered s340, which is not on sale but is still worth it for spots where you dont have the ability to hardwire.eufy Security Floodlight Cam S330: regularly $299.99, now $169.98 eufy Security Floodlight Camera E340: regularly $219.99, now $149.98 Best indoor security camera Credit: Aqara/Amazon I firmly believe that all security cameras should be able to pan and tilt. The ability to move the focus around the room and find what you need is essential, particularly for an indoor camera. It is too frustrating to be away and have something just out of range. For this reason, I have really liked the Aqara 2K Indoor Security Camera E1. Its solid, low profile, never gets knocked over, and allows you to sweep a room for exactly what you're looking for. Aqara 2K Indoor Security Camera E1, Pan & Tilt: regularly $59.99, now $39.99Best robot vacuums Credit: Amanda Blum I wish I could say that all robot vacuums, particularly the expensive ones, were comparable and that youd probably get a good one if you just spent enough. Unfortunately, that hasnt been my experience. Even within a brand, the variance from one model to the next can be jarring. However, Roborock models have consistently been my favorites over the last year. If I was going to buy a robot vacuum tomorrow, it would be from the Roborock S8 line. The S8 Pro Ultra is somehow exceptional on both carpet and hard floors. It has the fewest hiccups in terms of getting lost, getting stuck, or having to clear the rollers. The mopping feature isnt simply an add-onit competently gets the floor clean. Roborock S8 Pro Ultra: regularly $1,599.99, now $899.99 Credit: Credit: Switchbot/YouTube If you've got a smaller house, an apartment, or just a dedicated space you want to add a robot vacuum to, my far and away favorite is the Switchbot k10+. The diminutive size allows it to get closer to walls and around chair legs than regular bots of its kind. While technically a vacuum and mop, the mopping function isn't worth bothering withif you just focus on it as a vacuum, it will impress you. Switchbot K10+ Robot Vacuum: regularly $399.99, now $279.99Best smart diffuserThis smart scent diffuser, which I thought would be fun but nothing more, turned out to be one of my favorite finds of the year. Two aspects I love: You can turn it on and off or schedule it from your phone, so it doesn't get overwhelming, and you can load two different scents and it will show them in your phone app. The diffuser ($34.99) is currently 30% off, but that's no matter. Where you'll get stung is the refills, and many of those are 30% off right now, so load up. 2 Pack, Lavender Fields: regularly $27.98, now $19.592 Pack, Salt: regularly $31.98, now $22.39 The Best Black Friday Deals Right Now Apple AirPods Pro 2 ANC Earbuds With USB-C Charging Case $169.99 (List Price $249.00) Samsung Galaxy Tab A9+ 64GB Wi-Fi 11" Tablet $149.99 (List Price $219.99) Fire TV Stick 4K Streaming Device With Remote (2023 Model) $21.99 (List Price $49.99) Blink Outdoor 4 1080p Security Camera (3-Pack) $99.99 (List Price $259.99) Dell Inspiron 15 3535 Ryzen 7 1TB SSD 16GB RAM Laptop $449.99 (List Price $699.99) Seagate Portable 4TB External USB 3.0 Hard Drive $99.90 (List Price $124.99) Bose QuietComfort Wireless Noise Cancelling Headphones $199.00 (List Price $349.00) Deals are selected by our commerce team