LS Cubed: Little Sister Security System

RE: LS Cubed: Little Sister Security System

stewieman — Fri, 11 Sep 2020 10:55:28 GMT

Hey, [mention:cff82ed12b714001a1ba5205f2cb553c:e9ed411860ed4f2ba0265705b8793d05] this is exactly what I'm looking for, however, I'm a noob and don't really get header files. do you have somewhere where I can access these header files? I'm using 2 esp 32s. thanks so much.

Alex

RE: LS Cubed: Little Sister Security System

mcb1 — Wed, 25 Apr 2018 04:11:06 GMT

It certainly looks like it did trigger ... but as you say it wasn't until it was too late.

Well done, I think you have achieved the intent of the request.

More importantly your grandson might be able to appreciate the real world issues when these ideas seem so simple ....

Thanks for sharing and I'm looking forward to mine arriving.

Mark

RE: LS Cubed: Little Sister Security System

neilk — Tue, 24 Apr 2018 17:02:50 GMT

Hi Frank. Thanks very much for sharing that.

I could have done with something similar to protect myself from my little sister. She once got into my bedroom when I went to the bathroom. I'd been soldering and the iron was still hot - she picked it up by the wrong end!!!!!

Mother was not impressed

neil

RE: LS Cubed: Little Sister Security System

jw0752 — Thu, 19 Apr 2018 19:13:14 GMT

Hi Frank,

I really liked your project with your grandson. How cute that he wants to "bell" his little sister. I found his drawings excellent, understandable and frankly I have seen worse drawings from adults. I made something similar but simpler for one of my grand kids a while back. I called it a ninja detector and it was for me so I could protect myself from him sneaking up on me an scaring the stuffing out of me. Damn ninjas!

John

RE: LS Cubed: Little Sister Security System

fmilburn — Thu, 19 Apr 2018 05:56:05 GMT

Hi Mark [mention:8fb233e8974445138ef0af2b63b49f94:e9ed411860ed4f2ba0265705b8793d05] and others who have been following and kind enough to comment

The analog data from the RCWL-0515 "radar" sensor which Mark linked to has turned out to be quite interesting. Other than that link I haven't seen others trying to use the data so there may be opportunity to turn up a new use.

I wrote a quick Arduino sketch that lights LEDs according to the analog value coming off pin 12 of the RCWL-9196 (IC on the sensor board). See also the oscilloscope discussion above. I "rectified" the values in firmware - i.e. subtracted the midpoint from all values which gave me some negative numbers and then applied the absolute value to it. The analog output can be visualized through LEDs - the green LED on the left hovers around the high end of noise, the yellow LEDs are in the middle, and the red LED on the far right is at the top end of values read. Sampling is every 25 ms - any faster and the LEDs can't really be seen on the high end and any slower it misses the high end potentially. The sketch is also plotting the analog value on the screen behind it (the Arduino plotter auto scales which makes it somewhat harder to interpret here).

[View:https://players.brightcove.net/1362235890001/NkxiVJdjx_default/index.html?videoId=5773011651001:740:466]

Data can be captured faster but an oscilloscope is needed to make much sense of it. I am considering how this analog information might be useful. Certainly the blinking LEDs are nice but perhaps:

See through walls better
Detect more distant things
Detect smaller things
Etc.

But these questions will need more work to answer. Among the other questions I have been thinking about:

How long from power up does it take the sensor to become stable?
How many samples of the analog signal must be taken and at what frequency to understand the signal?
What additional data does the "negative" part of the analog signal contain? Is anything lost in the rectification?
Can the distance of an object be estimated from the signal?
What materials block the sensor?
Can the sensor be made more directional?

There is variability in the data I can't explain - e.g. I repeat the same movements but get different analog response. The IC the sensor uses seems to have a good algorithm for managing this variability to give the digital output.

I plan to modify the project to focus on the RCWL-0516 (remove the ultrasonic and PIR sensors) but still meet the original objectives. If you or others have thoughts on the items listed above please comment.

Regards, Frank

RE: LS Cubed: Little Sister Security System

three-phase — Tue, 17 Apr 2018 20:29:12 GMT

Interesting project, well presented with a good demonstration video. Thanks for posting and sharing with us.

Kind regards

RE: LS Cubed: Little Sister Security System

mcb1 — Tue, 17 Apr 2018 15:59:29 GMT

Nice project.

Seems you have a budding inventor there.

Great find on the 'radar' sensor.

They are a microwave device that uses frequency shifting to sense a moving object.

Most of the tests don't seem to include how far away they were when carrying out the experiments, but if they work to 5 m it's unlikely to be coupling causing the change.

I had heard about some outdoor sensors a work college had, and they worked extremely well. I imagine they have a similar device inside.

This blog would suggest the Vout is an analogue voltage

http://www.rogerclark.net/investigating-a-rcwl-9196-rcwl-0516-radar-motion-detector-modules/

It will work on a digital input and go high once it exceeds 0.5 x Vcc (2.5v )

Found some good conversations at https://hackaday.io/project/19400-first-steps-with-the-rcwl-0516-radar-switch

'Roy' used one for his cats ( don't tell [mention:2f7f3f52ea644a4ba1053d94e948bd06:e9ed411860ed4f2ba0265705b8793d05] ), and to log if someone entered his elderly neighbors premise while she was away.

Needless to say I've purchased some now.

Thanks

Mark

RE: LS Cubed: Little Sister Security System

genebren — Tue, 17 Apr 2018 14:28:14 GMT

Frank,

Fun little project. It is great that you and your Grandson are working together on a problem. Projects are fun for little kids.

Gene