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palcal

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Joined: 12/10/2011
Location: Australia
Posts: 1873

Posted: 10:58pm 29 Dec 2023

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I am trying to use one of these modules as a detector for an alarm, but the output always seems to be high even if I cover the module with a metal box. The datasheet says the output is "Inductive output high level" but I don't know what that means.
Has anyone had any experience with this module.

"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"

phil99

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Joined: 11/02/2018
Location: Australia
Posts: 2135

Posted: 11:50pm 29 Dec 2023

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Data sheet / user manual here
GitHub link here
Its described as a micro-motion sensor with 8m range so it probably needs to be fixed to a rigid surface with no moving objects within range.
Putting it in a metal box may be swamping the receiver as it is probably intended for a very weak return signal.

The manual mentions its firmware needs to be setup by connecting it to a PC (via TTL/USB adapter) and using configuration software "HLK-LD2420_TOOL".

palcal

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Joined: 12/10/2011
Location: Australia
Posts: 1873

Posted: 12:42am 30 Dec 2023

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Thanks, I have read all that, I just wanted to know whether it outputs a 1 or 0 on the output pin. I covered it with the metal box to try and stop it receiving any motion just to test but it still outputs a 1.
Edited 2023-12-30 10:43 by palcal

"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"

aFox
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Joined: 28/02/2023
Location: Germany
Posts: 76

Posted: 05:03pm 31 Dec 2023

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Quote The datasheet says the output is "Inductive output high level" but I don't know what that means.

Its like a translation of a Japanese user manual of a record player in the 70s. "Turn the arm 360° around."

I have some experiences using radar sensors in 80s and 90s.
These sensors detect not a motion.
These measure the time gap between sending and receiving.
Maybe anything is in the background reflecting the signal.
Set the sensitivity to the lowest level.
The sensor should now not detect anything.
If you still get a signal, there is a fault in the circuit or the sensor itself.
If you do not get a signal, increase the sensitivity gradually.
When you get a signal, turn the sensitivity back a step or two.
Now your sensor should be ready.

Happy new Year to all!

Gregor
Edited 2024-01-01 03:16 by aFox

aFox
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Joined: 28/02/2023
Location: Germany
Posts: 76

Posted: 04:20pm 01 Jan 2024

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My sentence "These sensors detect not a motion." needs a correction.

Some sensors compares two or more time gaps. If these are different a motion detection signal will be true.

Gregor

stanleyella

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Joined: 25/06/2022
Location: United Kingdom
Posts: 2129

Posted: 08:17pm 01 Jan 2024

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'VL53LOX instead?

OPTION EXPLICIT
OPTION DEFAULT NONE
Dim d$
Const i2caddr=&H29
I2C write i2caddr,0,2,&H89,&H1
Font 2
Pause 200
CLS
Do
getdistance
Pause 100
Loop
'
Sub getdistance
I2C write i2caddr,0,2,0,1
I2C write i2caddr,1,1,&H1E
I2C read i2caddr,0,2,d$
text 0,0,Str$(Str2bin(uint16,d$,BIG),3,0)+" mm "
End Sub

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