5PCS RCWL-0516 Motion Detection Sensor Microwave Radar Sensor Switch Module, for Arduino ESP8266 Nodemcu Wemos, for Human Rat Cat Detector, Distance 5-7m, Better than HC-SR501

This is for the microwave sensor, not the PIR. Confusing to have two separate products in one listing.... Anyway, the sensor works great. It seems to work only when at 5v, not the 3.3. At least in my experience. Just a word of warning, this thing is pretty much omnidirectional. It senses through walls and through floors. It's not entirely what I wanted, but I can't give it a bad review as it does what it's supposed to do, I just wasn't aware of it. Anyway, as an in-room motion detector it kidna sucks, as it will detect other rooms. Unless you have a Faraday cage I guess. I suppose it could be useful if you just want to know if someone is at home. In a flat, that's not so much use as it detects downstairs moving, as well as pigeons on the roof...

El producto cumple su función aunque es muy sensible (>4m de distancia probado) y casi omnidireccional por lo que para un uso dirigido hay que diseñar una guía de ondas. En mi caso particular hubiera preferido que el header de contactos viniera soldado pero tampoco es imprescindible.

The sensor is worked from the very first time with Arduino Uno WiFi Rev2. Very simple to use and detects motion well. We got it for school science project and had no trouble with getting it to work. You do need to solder the pins on the board but that is very clear from the description. The only downside is that my package came with 4 pin strips instead of 5 pin as shown in the picture. For the correct operation you only need 3 pins so that is not a problem. I just used my own pins but the included should also work just fine. There are number of examples online on how to use this sensor with Arduino. Over all the sensor is very good and the price is reasonable. I would recommend this over the PIR sensors, as I had better success with this sensor.

Great

An official guide to using these would be useful. After much experimenting I found that the likely reason they suggest you put this on the end of a cable 12" to 18" long is two fold. Firstly, you are supposed to leave 1cm of clear space around it. Presumably that's linked to the wavelength of the radar. If you mount it directly on a breadboard it has detection range less than 3cm. Secondly, if it's too close to other electronics, they can set it off. I had an ESP8266 WiFi module close it it, which set it of when the ESP came out of sleep mode. I tried placing it in bedroom and got false positives because it was sitting close to a WiFi router. If you know all of this then it's a very useful device and detects things very well. I ended up having to wake up the WiFi and ignore all the false positives coming from this device until the WiFi was back in sleep mode.

Work really well. I am surprised how sensitive and reliable this sensor is.