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My RCWL-0516 breadboard experiment

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jBo
 jBo
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Here is my implementation of the RCWL-0516 circuit for detecting motion, as seen in this DBWS video. Thanks very much @dronebot-workshop; I really enjoyed this experiment! I just followed Bill's examples for my circuit, but I thought I'd post my observations.

rcwl0516 latch breadboard

As others have noted, these are quite cost-effective little devices. I got a 10-pack. One seemed just defective, but that's not too bad. All the others worked. In my photo, I have three "extra" jumpers connected to the breadboard but just left open, sticking up into the air. I have found these very handy for testing the bare modules, BEFORE going to the trouble of soldering on the headers. In any case, 9 out of 10 work fine.

I used an Arduino Nano clone with USB, and with 5V for power to the RCWL-0516. I do use 3.3V for the little green LED, but I figure that doesn't make too much difference. The module was mounted vertically on the breadboard, using right-angle headers.

After running the experiment with the latch via push button, I noticed that even though I pushed the button, pulling my hand away triggered the motion detector again. I guess this makes sense, but I could never "escape" from the trap I'd built! So I added a few seconds delay for me to get away to a safe distance.

I wanted to test how far away it would work, i.e., the maximum distance where I could trigger the device. For this kind of testing, it got really old running up and pressing the button. So I put in a millis() timer to "forgive" myself after 8 seconds, even if I hadn't pressed the button. With this in place, I found I could trigger it from about 9 meters, which was out the door of my small lab/spare bedroom, and down the hall as far as I could go. The module is quite sensitive. I don't admit this easily, but a vertical shake of my shoulders did not trigger it, and a horizontal shimmy would always trigger the device. Do not picture this in your mind; I am not Kristi Yamaguchi. 😉 

I will post a separate note about issues with moving this setup to an ESP8266 and real world plans. Ciao, John.

 

In theory, theory and practice are the same.
In practice, they're different.


   
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Don
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For some reason, I have been unable to get the RCWL-0516 to work. I'm using the breadboard setup identical to Bill's video. When I apply ca. 5V to the power input, I'm seeing 3.3V from the regulated output. However, the sensor output only reliably triggers when I put my finger about 1/4 inch from the antenna.

I've tried 10 of these boards from two different vendors, but I get the same results from all of them. It would seem clear I'm doing something wrong, but for the life me I can't figure out what. I've tried different power supplies and looked through the long list of discussion topics on the GitHub site for the RCWL-0516.

Any suggestions would be appreciated.

 


   
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Will
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@donpk 

Maybe try this simpler circuit ...

https://create.arduino.cc/projecthub/hiotron/rcwl-0516-doppler-radar-sensor-interfacing-with-arduino-4c6ef0

Anything seems possible when you don't know what you're talking about.


   
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Ron
 Ron
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@donpk I will try the simpler circuit tomorrow.

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.


   
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Don
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@will That's actually the circuit I'm using, which is the same one used in DroneBotWorkshop video. It doesn't get much simpler: ground, 5V Vcc and the RCWL-0516 output which I've connect to an LED via a dropping resistor.


   
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Will
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@donpk 

Umm .. the sketch says to use pin 12 for the RCWL connection and pin 3 for the LED. The RCWL should connect directly to the Arduino pin, not be routed through the LED and a resistor.

To me, your description sounds as if the wiring is incorrect.

Screen Shot 2022 03 30 at 6.00.50 PM

OK, I understand now, you're not already using the same circuit as the article I sent you, because it's using an Arduino to read the sensor an you're not using a uController of any kind.

So, I'd suggest that you tip the sensor PCB board back a bit so that the antenna is pointing up and away from the desk.

 

Anything seems possible when you don't know what you're talking about.


   
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Don
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I'm using the simple circuit Experiment 1 from Bill's article:

image

If I can't get that to work, there's no point in hooking it up to an Arduino.


   
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Will
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@donpk 

Have you tried tipping the board back so that the antenna is not vertical or horizontal ? The surrounding area is not covered equally well in all directions.

Anything seems possible when you don't know what you're talking about.


   
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Ron
 Ron
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@donpk @jbo said 

I found I could trigger it from about 9 meters

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.


   
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Don
 Don
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@zander Nine meters, but not less then that?


   
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Ron
 Ron
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@donpk Have you read the OP?

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.


   
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Don
 Don
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I'm not sure. What is the "OP"?


   
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Will
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@donpk 

OP = Original Post (or Poster, depending on context)

Anything seems possible when you don't know what you're talking about.


   
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Ron
 Ron
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@donpk Original poster.

https://forum.dronebotworkshop.com/postid/21598/

 

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.


   
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Ron
 Ron
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Posts: 6662
 

@donpk I just tried the simple circuit, and it does not work very well at all. I triple checked the circuit, the LED comes on on power up, but then almost never reacts from a few inches away at least. I have a few of these and will try some more but I will first rewatch Bill's video to see his results.

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.


   
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