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I've integrated this doppler microwave detector to a raspberry pi 3 b+ and have been bench testing it -- and it works fine waving my hand in front of it.

I've now moved it to the area where it needs to be detecting and it doesn't seem to work through the window! It's a double pane window, and I'm standing in front of it moving. My foot is moving inches from the window and the detector leaning against the window. The sensitivity is set all the way up to just below where it triggers constantly with no motion nearby.

I don't understand --- my understanding is this sensor should work through walls and glass.

Or maybe not?

Even using the lower frequency 10 GHz spectrum means that 5G coverage would only exist inside of untreated glass windows, but likely nowhere else inside of a building.

What the heck is untreated glass?

Is it possible I have a defective unit? (Purchased locally through Jameco.)

...just to make sure also I have the orientation right -- the most sensitive side is NOT the side with the metal box, but the opposite side. Which orientation also has the widest spread? The card positioned in portrait or landscape?

Is the power output just not strong enough for my needs? Is there a better solution/product?

Specifications:

  • Working Voltage: 5V + 0.25V
  • Working Current (CW): 60mA max., 37mA typical
  • Interface: Gravity 3-Pin interface(Digital)
  • Size: 48.5x63mm
  • Emission parameters:

    • Detection Distance: 2-16M continuously adjustable
    • Emission Frequency: 10.525 GHz
    • Precision Frequency Setting: 3MHz
    • Output Power (minimum): 13dBm EIRP

    • Harmonic Emission: < -10dBm

    • Average Current (5%DC): 2mA typ.

    • Pulse Width (Min.): 5uSec

    • Load Cycle (Min.): 1%
  • Reception Parameters:
    • Sensitivity:(10dB S/N ratio)
    • 3Hz to 80Hz Bandwidth: 86dBm
    • 3Hz to 80Hz Bandwidth Clutter: 10uV
    • Antenna Gain: 8dBi
    • Vertical 3dB Beam Width: 36 degrees
    • Level 3dB Beam Width: 72 degrees

Edit: Ah, this is possibly based on the HB100, which has more detailed specs.

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  • \$\begingroup\$ The meaningful experiment would be to open the window, or if that is not possible, to find a piece of equivalent glass you can place or not place in a test setup. At present, you are basically asking a question about an unidentified window and the failure of a minimally documented system - meaning that this has a lot of the properties of an off topic "usage" question and few of those of an on-topic engineering one such as reducing the experiment to a single change with no other variables, measuring loss / reflection from the window, etc. \$\endgroup\$ – Chris Stratton Sep 3 at 14:25
  • \$\begingroup\$ I think I have a fundamental misunderstanding about the ability of 10 ghz to penetrate glass ... I’ve been trying to find articles to try to characterize the penetration power of 10 ghz to go through glass and have not been successful. \$\endgroup\$ – rrauenza Sep 3 at 14:28
  • \$\begingroup\$ The window does not open, but in place, I can activate the sensor. I think what I need is a subjective understanding of the power output of the device. \$\endgroup\$ – rrauenza Sep 3 at 14:28
  • \$\begingroup\$ If it was just glass, it would probably be ok, your problem is likely a metallic coating on the glass, especially since you mention it is a double pane window it is probably engineered to try to block some of the undesired components of sunlight. But the premise of engineering is that you don't just guess and assume that is the answer, you guess, and then investigate the guess - since documentation of micrwave transmission may not be available, you may need to conduct an experiment where the only thing that changes is the glass. \$\endgroup\$ – Chris Stratton Sep 3 at 14:32
  • \$\begingroup\$ yes! I think we have that treatment to block UV. It casts a blue green tint at night. \$\endgroup\$ – rrauenza Sep 3 at 14:33

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