UPDATE: Replaced my PIR-Sensor with a Doppler Microwave Sensor.

[Fozi]

@sdetweil Thanks! It’s fun to contribute to the community and this project.
If anyone has a better solution for the housing, I’d be happy if you post it here, too.
I am very sure that there a more creative approaches than mine.

[Mykle1]

@Fozi

Excellent description. I like your innovation. I’m guessing this is going to replace the PIR sensor. I think most people have the same feeling as you about the appearance of the PIR. It does distract from the “magic”. Well done! :thumbsup:

[Fozi]

@Mykle1 thank you so much!

[lavolp3]

@Fozi thanks for the great explanation. I tried to get one working but it didn’t work maybe for the exact reason you described.

Do you have it directly behind the glass now in your box? Without an additional resistor?
What do you think is the recognition length?

[Fozi]

@lavolp3 I have placed the sensor inside the box along the center axis, so that there is a gap of ca. 1cm to the front and the back of the box.
the UN-taped frontside is directly touching the glass. The top, bottom as well as the left and right side are taped, too. Only the front is not taped.
In the scetch below you can see how I adjusted the sensor inside the box as seen from the side.
Two reasons why I set the sensor in the middle of the box:

1. Direct contact with the tape prohibited fully the detection.
2. The taped top, bottom and lateral sides reduce the detection angle like a funnel compared to having the sensor mounted directly to the untaped front.

An additional resistor is not necessary, as it goes in high state when motion is detected (just like a PIR).

Hard to say what the detection range really is after that mod. My bathroom is really small but I would guess that if should be 2m or mor to the front.

Cross-section through the box:
||                                |
||               ||               |
||  1 cm gap     ||   1cm gap     |
||                                |
taped          sensor         UN-taped 
backside                      front to the mirror

[lavolp3]

@Fozi said in Replaced my PIR-Sensor with a Doppler Microwave Sensor.:

An additional resistor is not necessary, as it goes in high state when motion is detected

I thought a resistor could reduce the range by limiting the signals coming from the sensor. But I’m a complete failure when it comes to electronics so what do I know…

[Fozi]

@lavolp3 Ah…now I got you.
There are two options to reduce the sensor range:
Option 1: The aluminum taped “Magic Box” like described here.
Option 2: Replacing a resistor on the sensor to reduce the sensor range.

I haven’t yet tried option2, as I’m waiting for some parts to do it. As soon as I got them I’ll test that option and will give feedback. For the time beeing, I just can make a statement for option 1, which requires no additional resistor.

Maybe there is also an option 3, a combination of option 1 and 2…we’ll see.

[cowboysdude]

@Mykle1 said in Replaced my PIR-Sensor with a Doppler Microwave Sensor.:

@Fozi

Excellent description. I like your innovation. I’m guessing this is going to replace the PIR sensor. I think most people have the same feeling as you about the appearance of the PIR. It does distract from the “magic”. Well done! :thumbsup:

That would be the idea…easier to ‘hide’… the PIR is nice but ugly.

[cowboysdude]

@Fozi said in Replaced my PIR-Sensor with a Doppler Microwave Sensor.:

RCWL-0516 microwave sensor

Thank you so much for this…ordering one so I can get rid of the ugly PIR in my bathroom!!!
Awesome job!!

[Fozi]

@cowboysdude Thanks! I’m looking forward to your experiences with the sensor!

[lavolp3]

@Fozi
I’ll try this out hopefully tonight but not with an Aluminium tape but with aluminum foil. Should work as well as far as I can see.

[Fozi]

@lavolp3 yes, should do equally. I had some leftover of the tape and it was more convenient to apply. I found some post from you a few months ago, when you struggled to make the sensor work. I hope you get some better results now.

[cowboysdude]

@Fozi Is there a wiring diagram for this? I know where the wires on my pi are and there two wires running to the sensor but where are they connected on the actual sensor?

Thanks!

[Fozi]

@cowboysdude
You only use Vin (5V), Vout and GND. CDS (for applying a photo diode) and 3V3 (delivers 3.3V output) remain unused. For Vout you can use also oher GPIO pins (labeled “Digital I/O” in the 2nd diagram), in case GPIO_4 is already used.

The ferrite bead is optional. It is a left over from the PIR sensor I had attached. If you may need one, you can dismantle an old VGA cable and use that one.
Here the wireing diagram:

[cowboysdude]

Super Awesome yet again!! Thank you! I don’t use the PIR module… I have a Python script I run behind everything. It works very well for me but this will work so nice, and now I can move it behind the glass!

Now if I can just remember where I put my ferrite beads… I know I have some … but where LOL

[Fozi]

Hi folks,

sooner than expected I modified the sensor with a trimmer resistor.
For that I also updated my initial post and enhanced the tutorial, where now both options are described. Enjoy and give me your feedback, how that works for you.

[sdetweil]

@Fozi nice update… very clear and helpful

[cowboysdude]

Once again excellent work! I love the trimmer it’s a great idea for those with limited space!
For some strange reason I have left a gap at the top of my mirror that fits what I build perfectly!
I wanted a bigger mirror so I bought the glass oversized and centered the monitor in it :)

This, accidently, left me enough room to fit this in perfectly!

So what I did was design a “T” with a whole in it to mount the sensor and install it inside the box.
I am a contractor so having aluminum tape was not a hard thing for me to come up with.

Thank you @Fozi for this entire project! Allows me to get rid of the ugly PIR sensor outside the mirror and place a sensor behind the scenes but works as intended.

So for me option 1 works great! This won’t work for everyone but in my case perfect!
[Have NOT installed it in the mirror yet but will today]

Here’s the pictures.

Box

3d PLA Printed ‘T’

Fits inside of box

Picture of sensor on ‘T’

Once again, Thank you @Fozi !!!

[Mykle1]

@Fozi said in UPDATE: Replaced my PIR-Sensor with a Doppler Microwave Sensor.:

sooner than expected I modified the sensor with a trimmer resistor.
For that I also updated my initial post and enhanced the tutorial, where now both options are described.

Dude, (can I call you dude?) although I don’t use a sensor (I have a cam on my first mirror w/Pi) I appreciate what you’ve done here. I’ll say it again (in different words), I think this is the death knell of the PIR sensor. So, thanks. :thumbsup:

Peace!

[Fozi]

@cowboysdude I‘m totally happy that I cold help and to receive so positive feedback! I love it when a plan works!😁 Thanks!
This T-shaped holder, is it 3D-printed or an off-the-shelf available part? It‘s totally cool!