For as long as I remember, I wondered why we don’t have a universal sensor node to supply all the environmental data to your home automation. One device to supply all the most important room metrics. SwitchBot Contact sensor got close, but Shelly Motion2 is nailing it. It’s not just a motion sensor, it’s everything!
Shelly Motion2
“2” at the end means there was a Motion Sensor (1) – and while the concept was interesting thanks to always connected WiFi motion sensor with lots of interesting functions, the actual device was a little bulky and expensive. It’s been years, and Shelly has been busy gathering feedback and making new devices. From the new and improved Shelly Plus line to Shelly Motion2 – a sensor that you should definitely consider regardless of the type of automation at home.
Just like the original sensor, Shelly Motion2 is a WiFi-enabled sensor that links with a 2.4GHz network (or creates its own AP point for situations where wireless LAN isn’t possible).
Shelly Motion2 isn’t just about motion. It brings the most important metrics to your automation: motion, light levels, vibration and temperature. One could argue that humidity would be nice, but honestly – I’m excited as is.
One battery-operated device delivers all that data that lasts up to a year on a single charge (Li-ion 3.7 V / 6500 mAh). As the device is straight from the production line, I can’t verify the claim, but I had it running for over a week now and it still reports 100%. That’s promising. What’s nice is the included USB-C port for easy charging.
The only complaint I have at this point is the mounting bracket. While the device clips well and is attached firmly to the bracket, I had to put a lot of effort into limiting the movement of the ball joint – I went to town on the screws at the back to add friction to that joint and keep Shelly Motion2 in place.
As a motion sensor
The main sensor of the Shelly Motion2 – a highly customisable motion sensor capable of detecting motion up to 9m – is enough to cover most of the household areas. The minimum timeout for the motion is 1min, which may not be as impressive as a 1-sec timeout on ZigBee-based Aqara Motion P1, but the device comes with interesting trigger options.
Motion triggers can be associated with a schedule and brightness levels. Settings allow Shelly Motion2 to set the number of consecutive motion events (1-4) before the notification is issued and the timeout can be increased up to 1440 min.
To control the sensitivity of the sensor you have a slider with 255 levels of sensitivity – you will definitely set it to activate on important events. As I don’t have pets, I can’t really verify how reliable this would be with having/not having pets trigger the sensor.
Unfortunately, there is no log of the past motion triggers so if you want to keep a record of this, you will have to use associated webhooks or MQTT to store it yourself.
As a temperature sensor
Shelly Motion2 doesn’t have a humidity sensor on board. For that, you will have to get their dedicated Shelly T&H Sensor instead. Apart from bathrooms and perhaps the kitchen, I’d be absolutely ok without that metric. Temperature is most important to me.
The temperature is updated in 5 min intervals or based on sudden changes in temperatures (within 30 sec). Looking at my other sensors scattered around the house (check out my write-up on best ZigBee temperature sensors) – the sensor is accurate to about 0.7C – that’s without actual offsets. You can tinker with these more if you require higher fidelity of the reading. I’m satisfied with the accuracy as is.
History
Not everything is by the book. While the temperature in the device card is updated every couple of minutes, the graph in the app displays the average temperature at hourly intervals. It’s frequent enough to give you a general idea about the environment in your house, but not frequent enough to perform an efficient analysis of your heating system.
Fortunately, you are not locked to Shelly Cloud and you can utilise various options to store all updates via NodeRED and display it with InfluxDB and Grafana. It’s more work to set up – but all Shelly devices are geared up to work with 3rd party.
Apart from temperature offsets, settings allow you to set the units, and monitor the threshold to increase or decrease the recording sensitivity.
As a brightness sensor
Brightness information is provided in lux units and ranges from 0 to 100000 and provides 3 light levels available as triggers: dark, twilight, and bright. These can be also defined in the sensor’s settings so if you don’t like the specific values for each trigger you can change the ranges.
These triggers can be used to narrow down other actions so they apply only at night or at certain light levels. Especially useful for changing the behaviour of the bulbs at twilight and at night. There is no historical data associated with this measurement, so if you want to have a record, you will need to use webhooks or MQTT to get that info out of your Shelly Motion2.
As a vibration sensor
Acting as a tamper alarm and potential warning system for earthquakes, the vibration sensor displays extra info in your app when the shakes are detected. Sadly it’s a binary notification, so you won’t receive the information about the strength of the motion, but you can calibrate this in the settings to fit your needs.
It’s pretty sensitive at low settings, and I could imagine this can be activated by passing lorries outside if your walls are prone to movement like this. With a bit of trial and error, you could use this to create an earthquake alarm, in case you sleep as deep as me.
Shelly app
What I really like about Shelly Motion2 is the fact that it comes with Shelly Cloud and a web interface. It means you get to choose how you take advantage of the sensor. In the typical scenario, where the sensor is connected to Shelly Cloud, you can interact with it via the app, connect it to Alexa and Google Home via relevant skills and use it as a trigger for motion, temperature range, vibration and light.
On top of this, each activation can send a webhook (web request) to trigger 3rd party systems like Home Assistant or NodeRED and deliver the payload with Shelly Motion2 data. If privacy is your primary concern, you can disable the cloud altogether and use REST API or MQTT to build your automation from scratch – an always-connected web interface will give you all the options you need to configure that.
Each time Shelly releases a new device, I always know whatever path I choose, the firmware is always there to support my decision. I only wish more companies would take this approach: give us cloud connectivity as default, but DIY connections as an option.
Get Shelly
Check out other devices from the Shelly series to build your ultimate DIY automation:
Final thoughts
The original Shelly Motion was expensive and big. Shelly Motion2 balances the size, battery life and features very well without burning a hole in your wallet. The sensor will set you back just under €40 (plus VAT) which is reasonable considering that you are essentially getting 4 sensors in a single node. As usual with Shelly products, extra points are awarded for not making it hard to get that environmental information out of their ecosystem so you can use it in your DIY home automation. Are you equally impressed? Let me know in this Reddit thread.
🆓📈 – See the transparency note for details.
