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

[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!