5 PCS RCWL-0516 Microwave Radar Motion Sensor Module for Arduino Smart Switch Module Human Body Induction Module 5-7M Detection Distance 4-28V 100mA

I'm designing a security system for home and after reading past reviewers decided to order a pack of 5 of these radar detectors. Out of the box, only one worked, detecting body movement about 12 feet away. The other 4 only saw movement about 4 inches away in any orientation.Just before dumping them, on a whim I tried something. I exposed a small area of trace from the collector of the colpitts transistor and soldered a short (3/4 inch) piece of wire as an antenna (see the picture). To my glee, three of the units were then able to detect movement about 10 feet away. One still never worked. The second picture shows the test circuit (with a 12V supply). This may not work for everybody, and you do need a fairly steady hand so as not to fry something. But I am disappointed at the overall results.MAJOR EDIT. STOP PRESS! Two weeks later.......While browsing some user experiences with these modules, I came across another user's discovery that these modules do not work when plugged into a breadboard, because of the amount of nearby metal. All my comments above were based on using the module plugged into a breadboard. So I unplugged it from the breadboard and connected it by 3 wires (power supply and output) about 8 inches long. And VOILA, success. They worked flawlessly, picking up movement nearly 20 feet away (without my little antenna). I am now so happy. I have changed my 2 stars to a full 5.I offer a full apology to the makers for my original low rating. However they should warn prospective buyers about this behaviour. It would have saved me a lot of grief.

A simple Transistor based oscillator with quite an impressive range. Quite stable with sudden temperature shifts (rework station blast at low temperature) Adding a 2.2uF-4.7uF ceramic or low ESR capacitor at the 3.3v out pin did improve the response a few percent. (makes the IC Comparator / OpAmp reference voltage more stable) And at least 10uF to 47uF at the power input for decoupling depending on line noise and any expected pulsed brownouts. Using regulation to a lower than supply voltage staying above 3.7v at least can help to reduce noise on power lines as well as a capacitor of 10nF to 100 nF from PCB GND straight to Earth can help remove noise immensely and reduce / remove frequency loop. (frequency loop is more towards capacaitive sensors than inductive). The whole board and power supply lines can become the antenna.The RCWL-0516 has not shown this "loop" behavior. (Transistor driver by design is better isolated) The add on LDR with an ability to bias the LDR with the resistor input R-CDS is nice.The output drive current is low even for 3.3V, External driver does help in that case if needed above a few mA.Range is effective by 15-18 ft. If the rate of angle and mass were aligned with the antenna (aimed) then the range can go further. (Walking to or from the antenna). The side angle distance is also good as is the aft angle, tho that was not a key test here.

It appears to be a nice module and when it first powers on it looks to work. It lights up and then after a second or two the output goes low. once it sees movement the output goes high. Here is where I have issues, mine will start flashing. Several people mention using a filter or decoupling cap or a large filter cap 1000uf or larger. what I would like is more info/application notes. What is the best orientation for it to pickup motion? What filters do I need and where should they be placed.I worked with it a bit more the Flashing I experienced was caused by the input VCC close to the low VCC range. I increased it and it seems to be a bit more stable. With the modules I received the range is very limited. 3" to 6". This will not do what I am needing, this only senses motion and if the motion is not constant the output will go low again. slight motion such as breathing is not enough to trigger these.

After using these for a week or so here’s what I learned:Decouple the wires from the sensors. Use ferrite beads on the wires at the board.When the sensor is placed near a large metal object (ie. on a rung of a metal ladder) the range is increasedand the detection is more consistant.For longest range the sensor should be horizontal. Doesn’t matter if the components are on top or on the bottom.The sensors don’t seem to interfere when spaced 6 inches or more apart.If placed in a two story structure they will detect movement across floors but only directly above or below.Considering the cost, these are impressivly useful little devices.

Easy to use, no documentation though. 1 in the pack didn't work.Unit is very sensitive, I needed to use software calibration to reduce the noise.

I'm happy with the radar sensors I received. They work quite well and are easy to work with. The default reset timer is short at about two seconds, but this can easily be resolved by adding a capacitor at the C-TM location. 1uF cap yields about four minute reset delay, a 2.2uF cap gives me just shy of ten minute reset...perfect.

It doesn't get any simpler for a microwave-based motion sensor. I wired a digital pin to the OUT pin of this sensor with a 220-ohm resistor, the VIN pin to 5V power and the GND pin to ground. Also wired up an LED to turn on or off based on reading that digital pin, and it works every time. Specs say the tolerance is "5 to 7 meters" and I've tested this up to 20 feet from my workbench and the LED accurately echoed my movement or stillness.

I used this sensor for my project. It seems ok for the first time and actually price and sensing distance is right for me. But, as the tike goes, something was wrong. And I found that the sensor output is totally random sometimes. I could fix the problem by adding my signal processing algorithm from the analog pin(#12). But it is not suser friendly.