RCWL-0516 Microwave Doppler Radar Sensor Module

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.

I'm using this outdoors, hidden within a piece of cedar, inside a small piece of pvc pipe, mounted on a 4x4 mailbox post. Thus, there's ~1/4" of wood plus the pvc in front of the sensor, and 3 1/2" of wood plus the pvc behind it. It senses people or cars at up to ~15 feet in front, and totally ignores any movement behind, which is perfect for my use. When used indoors, the sensor is just too sensitive, and can be tamed if you're skilled with a soldering iron, by attaching a 1MegOhm resistor between points R and GN on the board. When used outdoors, with the added resistor, the sensor essentially does nothing, but works perfectly as described above, without the resistor. I've thus far tested 4 of the 5 received, and they've all worked.

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.

I tried one of the boards out and got about the advertised range for detection. I noticed that the board gets "sensitized" and gets repeat detections at longer ranges than the initial detection. I tried aiming the board through an interior wall (drywall with no wiring in the beam). It seemed to get about as much range as when it was in the clear. This would be useful for covert intrusion alarms with nothing showing. I suspect that it won't do as well through an exterior wall, but didn't try that The board operates on about 3 ma, which is quite a bit more than the IR motion detectors, so larger batteries will be needed for extended operation. Interesting product!

I had panned the purchase as I couldn't get the first one I tried to latch at less than 2 cm. Just for giggles I took another board and instead of using a header I used 24 ga. solid hook up wire. I had some scrap pieces about 2 " long so I hooked it up and the board worked. It triggered at about 1 m. I began to wonder if I had overlooked something in the description of the board. There was nothing in the description that indicated there was a minimum length for the hook up wires. So I went to the github link and found that the author recommended at least 18" of wire be used to connect the board. I took the original board that allegedly did not work and connected it to the protoboard with long wires. Lo and behold it worked! I would recommend that if the seller wants better reviews they should be a bit clearer about how to hook these boards up. I wasn't happy with the way the boards were packed - loosely all in the same antistatic bag. Now that I have found out what is required when using these boards I'll do some experimenting to determine the actual minimum length needed to hook these devices up.

If you have tried using the PIR modules (looks like a bug's eye) with ESP-based MCUs, you find that you get a lot of false positive readings. That's because the shielding isn't stopping the Wi-Fi signal from triggering the PIR. These modules fix that. The only warning I have for you is this: They are sensitive. The first time I hooked one up, it kept triggering. I was holding it in my hand. When I place it on a table, it was fine. If you're looking for thermal-based sensors that are sensitive, pick up a pack of these.

I connected the modules to 5V, ground and output to an oscilloscope to view the response to motion. All 5 modules behaved precisely the same: 1) on application of 5V power to Vin, the 3.3V regulator output produced 3.3V. Good! 2) then the signal output went high for several seconds. Also good, proves the control IC works. 3) never went high again in spite of motion around it, until I put a finger within 1" of the sensor on either side. One inch is NOT seven meters. NOT GOOD... the RF oscillator is not working very well, it seems. FAIL. I have to give the designer credit for innovative thinking, re-purposing the IR sensor IC for this function. Too bad the oscillator power is too low to fulfill the purpose of the product.

I have 4 of these placed in close proximity and coupled with LDR's for night use of video lighting. They work well.

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.

Great

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

All 5 boards had a roughly 2 inch range. Varied cable lengths and varied voltage supply made no difference. Ordered twice - first order came with no headers and was returned. Re-order also came with no headers and all boards had such limited range as to make them useless.