SONOFF DW2 WiFi Wireless Door Window Alarm Sensor with Phone Alerts, No Hub Required, Works with Alexa & Google Home, Low-battery Reminder, 2.4GHz WiFi Connectivity

works a treat, the single AA battery has lasted well over and year, it has not lost connection once.And it triggers every day to alert me via Google Home. Considering it requires no bridge device (as it's wifi connected) its a fantastic bit of quick for a good price

I was impressed how easily these were to set up electronically. Although I did have a little difficulty in siting the one on a door that did not close flush with the frame as both the items need to be lined up flush. Initially I was quite happy with the setup. So much so that I nearly ordered more. However, 24 hrs later and I was being advised to change the batteries. after a further 12 hrs they stopped working. Maybe I had a bad batch of batteries. Bought new batteries and fitted them. Hey presto everything working fine again. That was short lived. 12 hrs later I'm being advised to change the batteries. So unless you intend to change the batteries every day then they probably aren't what you want. Easy to set up but a nightmare to maintain! I would have expected the batteries to last at least a month!Steer Clear!

Unless the unit I got is somehow defective (but I'm not going to buy another one to try it), this product is a joke. Battery life is terrible, the first set of batteries (2xAAA) I used lasted for about 7 days. The second set only lasted less than 3 days!Look at the graph taken from Home Assistant, the one named as "Fridge Door Battery" is this Sonoff sensor. Battery went down to 70% after just a few hours, and then became erratic until was completely drained a few hours later. Compare to the other graph (Contact Sensor Batter), this is from another similar sensor (different brand), but the battery has been solidly constant at 100% during the last 3 days.Battery is supposed to last for about a year in these kind of sensors. I already spent more in batteries than the sensor itself, and now I'm with a useless piece of plastic.The sensor itself works well when is poweredUpdate 03/10: Sonoff after-sales contacted me and after a few tests, they recognised the product was defective. They offered sending me a new sensor, but since I've already got another one, I opted for a refund, which they promptly did.

The media could not be loaded. If, like me, you have kids that leave the freezer open, and you go to it the next day and find all your expensive meats thawed out, it drives me crazy I have to throw all that meat in the bin. Well no more wasted meat!!!I like this because.....- Easy to install- Notifies me via notification- Simple and effective- Low cost- Two AAA batteries and install within seconds. I use amazon basics researchable batteries, these are great too.Hope you like it like me :) Well done sonoff, big fan!

So, functionality wise these sensors are spot on. Pared to the ewelink app no problem, then to Alexa, Goole Hone and Home Assistant. However, these are battery powered devices and as such the have a VERY limited WiFi range.I have one device with a 2.5m direct line if sight to the WiFi AP and the RSSI is -89db, my second device is 5m from the same AP and is reporting -101db (my phone reports -56db at the same position). These figures are appallingly bad, but just enough to be functional. In summary, your going need excellent WiFi coverage for these sensors to work. Look at the RSSI figure on your phone at the position you want to place the sensor. If this is -60db and up, then forget it.

I bought this product with a attempt of simply trying to expand the functionality of my current sonoff light switch. However after reading some negative comments about it, I have to say it did almost put me off from buying this great productI have been using this for almost 2 weeks and I have never come across with any issues what so ever. Setup is piece of cake, no wires just battery powered and simply stick on to the door with the supplied 3m sticky pad. What amaze me the most is the responsiveness, as you can see from my video, it turn on/off almost instantly.For those who used the ewelink app, this is not going to any issues, you just simply setup the the device to trigger an action on your WiFi switch using 'scene'.Please don't let the negative comments put you off buying this great product and try it out yourself. I will give me more stars if I could simply because the functionality/cost.

Works fine and easy to install but goes through a set of batteries every few days. I have tried rechargeable as well as non rechargeable Alkaline and long life Lithium batteries. None lasted more than 3 days. I have now installed a separate 3v supply and ditched the batteries.

Firstly, the setup instructions are not fully complete so you have to try and guess what they are trying to ask you to do. Looks like the app has been updated but the printed instructions haven't been.Once setup the device works as it should do but the smart features do not. To use the smart features other devices must also be ewelink ones. So tried setting it up with Google assistant. It does pair but you can't do anything. It doesn't show up as having any functionality in the assistant app.It does support ifttt though. But when trying to add it you need to upgrade your ewelink account to a pro version for 10 dollars a year.Have returned this and will not be buying anything else from ewelink.