Zigbee rain detectors are popping up all over my feed. These are small binary devices built to do one job: detect rain and stop your lawn mower from mowing through a downpour. Even though they rely on the most basic hardware implementation, not all of them are the same. After all, someone actually decided to design and release a non-waterproof rain detector as a finished product.
Among the better, waterproof options, I’ve tested the solar-powered Tuya XFY model and the sunflower-style Tuya RB-SRAIN01. Both perform well, but if I had to choose, I’d go with the XFY. It’s smaller, easier to wall-mount, and appears to be better waterproofed.
In this article, I’m reviewing the eWeLink MS1 Zigbee Rain Sensor. Unlike the XFY, it is not solar powered and runs on two AAA batteries instead. I have been testing it side by side with the XFY for several days to see which one is the better sensor. You can get it on AliExpress, Amazon DE, Amazon UK, or Domadoo (EU).
What’s inside the eWeLink MS1?
The eWeLink MS1 Zigbee Rain Sensor ships in small box containing the device itself, a sticker, a set of screws with dowels and a user manual. The packaging is pretty basic and of low quality, but the device feels well made and sturdy.
The water detection plate features an interesting snake-like pattern rather than simple straight lines running end to end. The device itself feels compact, though very light without batteries installed. It is solidly built, with no rattling or loose parts inside. On the backside, there are two holes for screw-mounting this rain sensor. I feel like this is a must, since the sticker won’t hold for long out in the rain.
The batteries are installed under the back cover. There is a small pairing button between the two AAA batteries and a rubber gasket going around the frame of the sensor. Once assembled, the backplate clicks into place, creating a seal that protects the internals from water and dust. The sensor carries an IP65 rating.
Despite what the poor packaging promises, the device is actually well made on the inside. The PCB is clean, neatly organized and professionally put together. This sensor is powered by the Telink TLSR8656 [Datasheet]Â module, found in many Sonoff/eWeLink devices like the S60ZB Smart Plug or the SNZB-02WD and SNZB-02LD Temperature Sensors.
The main PCB connects to the plate with two wires running underneath. Both contact points are sealed with a protective coating to keep water and dust from entering the device from the front. Interestingly, the PCB is labeled as made by MAIFAR, which appears to be a tech company active in the smart home space. They produce various smart products including mmWave presence sensors for the eWeLink ecosystem.
Home Assistant Integration
The eWeLink MS1 is supported in both Zigbee2MQTT and ZHA in Home Assistant. To pair it to your coordinator, open the battery cover and press and hold the button for 5 seconds until the LED starts blinking. In both integrations, it’s detected as eWeLink SNZB-05, since it appears it’s built on top of this water leak sensor.
Zigbee2MQTT
The device pairs without issues and gets labelled as SNZB-05 water leak sensor by eWeLink. This is happening because the device is built from this sensor, using the same module and ID to go around certification fees. The same clusters are usable here, so the device works like it should. It exposes the following entities in Home Assistant through Zigbee2MQTT:
The binary water leak sensor reacts instantly, reporting a state change the moment water is detected or the plate is touched. This also works the other way around, clearing the leak immediately once the plate is no longer shorted. For automations, it is often best to add a short delay, since the rapid clearing can otherwise cause false triggers.
ZHA
Once paired to ZHA, the device is also identified as SNZB-05 by eWeLink instead of MS1. Again, it does not matter as the device operates well and the binary water leak sensor is fully functional. Development of a custom quirk is not required, as you would gain nothing.
Testing the waterproof seal
Just like the Tuya XFY, I mounted the eWeLink MS1 on my office door with a sticker. Both are IP65 rated, which means resistant to dust particles and water jets from all directions. I started to pour water all over the eWeLink MS1 and did so for a good minute, just like I did with the Tuya XFY.
The sensor triggered immediately in my testing instance of Zigbee2MQTT. I let it dry out and dismantled it again to check for any leaks inside the device. Unsurprisingly, there were none and all was good. The rubber gasket was doing it’s job and the MS1 was alive and well. Interestingly, the sticker held too and the device remained in place.
Final Thoughts
If you are looking for a simple binary rain detector, the eWeLink MS1 is a great pick. It feels compact, well-made and well protected from water and dust ingress. It works with ZHA and Zigbee2MQTT out of the box, so you don’t need to worry about creating converters or custom quirk handlers.
If I had to pick one between the eWeLink MS1 and the solar-powered Tuya XFY, I would choose the MS1. To me, a solar panel is just another point of failure and not worth the hassle in a device of this type. This kind of sensor is going to spend 90% of it’s time sleeping so you can easily get a full year of battery life on a good set of AAAs in the MS1. Here’s where you can get it:
Alternative links: Domadoo, Amazon UK, Amazon NL, AliExpress 2.
