As there are not many radar / microwave sensors with ZigBee on the market, I was looking for a solution to meet my demands. Without Tuya / Smart Home (they do offer such products). I’d like to introduce my solution and how I solved problems.
“Huber motion” is offering pretty good radar sensors for a low price, I use approx. 10 of these since years. Unfortunately they do not offer anything with ZigBee.
My idea was to couple e ZigBee switch / relay with one of these three wire 240V - motion sensors.
On the ZigBee side, you’ll need a ZigBee switch suitable for an external switch, and NOT a >push switch>. The suitable model is:
Sunricher SR-ZG9100A-S
I use the SunRicher type as well as this one:
NodOn
An example for a three wire radar / microwave switch is:
Motion Sensor
The motion sensor and the ZigBee switch you’ll wire to “L” and “N”.
The light output of the motion sensor (L’) you’ll wire to the switch input at “S1” (Giving an “L” signal to “S1” will trigger the ZigBee relay for as long as “L” is applied to “S1”; no signal to “S1” and the relay falls off to Zero state). So far so good!
When you test it, you’ll find out, that the switched “L” signal of the motion sensor will NOT trigger the ZigBee relay. You’ll need a “interference suppression capacitor” to reach your goal. One leg of the capacitor you’ll connect to " L’ " (lamp output) of the motion sensor and the other leg you’ll connect to “S1”. The capacitor should be able to resist the net voltage (i.e. 270 volts AC) and have a capacity of approx. 0.22 uF (MicroFarad). So you’re done. The capacitor was the trick.
These capacitors are often used in LED installations, when after switching off, the LED ist still flickering a bit at very low level.
Everytime, when the motion sensor triggers, you’ll get an ZigBee “on” signal for the time set by the motion sensor (you can also set brightness level and sensitivity at the sensor).
What do I use this for?
We are running a fashion shop. For energy saving reasons, at night time, the shop windows are NOT always illuminated. The lights are controlled by such a motion sensor / switch installation in each window. A normal PIR sensor will not work through the windows glass, but a microwave / radar sensor does work through the glass. It is even sensitive enough to detect passing car in 7-10m distance. I adjust the sensitivity in that way, that pedestrians (in 1-3 meters distance) trigger the light and cars in 7-10 meters distance do not trigger.
So every time a motion is detected, I start a dynamic light scene in the according shop window. Without motion there is only a “basic” light at very low brightness.
My experience is, that this attracts people walking along the window much more, than a continously lighted window - and it saves energy!
The sensors are at the upper end of the room mounted in 3p-track outlet. This makes them mobile and grid supplied with power.
Also in our fitting cabins, I use this to dim up the light to max. level with 5 seconds transition time and dim it down again after a few minutes with 30 seconds transition time, when there is no one in the cabin. The microwave sensor in this case is behind the big mirror and works through it.
The same setup, I use at home, where PIR detecting sensors are not reliable enough and on the other hand, I am not keen on changing batteries in 20 sensors around the house.
Have fun!
