SONOFFDW2 Wi-Fi Wireless Door Window Sensor,APP Alert for Home Automation Wireless Alarm Security System, Compatible with IFTTT, No Gateway Required.

Very good product. The only con I find is that it's not rechargeable and you need to replace the batteries.

This product is useless. Does not work in modern networks. I was able to pair the two units, but they never connected to the ewelink network. There are lot's of complains about this (which sadly I did not read before purchasing). I had several Sonoff products and work fine. This should not be selling at all. Don't waste your time and money.

I use it in the mailbox in our front yard. I was concerned that the WiFi range would be an issue but the signal strength is very good. The batteries are AAA. So replacing them is affordable.I use it in Home Assistant to notify us when we have mail. It is 100% reliable for us. Highly recommend it.

First, I'm not using this as a door sensor. I wanted it as an out-call notification when my alarm panel is activated. Located at a rural cabin, the alarm panel drives a siren so used that output through a relay to activate this sensor, which in turn provides a push notification to my phone. It did not pair up like my other Sonoff switches, but found that the bluetooth pairing option went smoothly and quickly. At this point, it does everything I wanted it to do - just hope it has longevity I also substituted a 3 vdc power supply for the batteries so I can't properly assess battery life, but none of that would apply to its expected use as a door/ window sensor. I did play with it using the included magnet, as well as other magnets, and the greatest sensitivity appears to be above and below the alignment mark on the sensor - nearer the ends of the reed switch inside the sensor. The included magnet also needs to be in very close proximity to the sensor - minimal spacing - and that could be an issue in actual application. If I were using this as a door sensor, and couldn't obtain the minimum spacing required for consistent holding and triggering, I would probably substitute a stronger magnet. I tried various combinations of rare-earth disc magnets made for fridge clips, and found I had a much better range of sensitivity without the need to keep spacing so close - and once the door opens, any field effect is gone and you still get a trigger. Get past the pairing and it should do the job.

I have been looking for a WIFI door/window sensor that is practical and easy to install and use. Well if you're looking for that same thing then look no further.It took me just few minutes to download the app, setup an account and detect each sensor to make sure it works and then fix it on my door and voila .

Device works , when batteries last. Present batteries last approx 3 days. Hope a software update solve this.

Sonoff is easy to install and has a great phone app. I attached this to my garage door, and I get a "bing" on my phone when the door opens and closes. Amazon uses Key delivery to place items in my garage, so I know that they've been there and not to drive over the box that they left. That actually happened once. I know when my wife gets home. Very useful, easy to install. It also tells you when the battery is low.We've hacked it to allow a switch to activate it, controlling it with an electromagnet.

Sensor works well, once you get past the setup. Took several attempts to link up.I read some reviews that say it goes through the batteries, but haven't seen that. I bought this back in August of 2022. It's been in use since then and still on first set of energizers. It's now beginning of April 2023. It is mounted about 20ft from an access point and in sight. Probably has something to do with it. I use this to detect open or close status of a garage door. If door is detected open at 10pm, ewelink will auto close using another sonoff relay controlling door opener/closer. If I needed another one, I wouldn't hesitate in buying it.Update 9-20-23Something with this has changed a few months ago. Setup is still the same, but now it drains the batteries in less than a week! It's also going offline 50% of the time. It's pretty much useless now. Not sure that I will try another one. Down to one star from 5.