PIR Sensor 24v

[SFisher]

Hello, I tried to look for use a cheap pir 24v sensor on this forum, but it's a pity I didn't find this one...

I need a pir sensor for stairs's light - so it should be minimal size...
Don't want to buy expensive sensors like occy for stairs...

Anyone has experience with using such PIR sensors with loxone:

https://www.aliexpress.com/item/1005004418972434.html

They have output 24V while sensor voltage on AI should be 0-10V

I thought about adding a convertor 24V to digital output, but didn't have any experience...

Can please someone help me with this question?

Thanks

[Jan W.]

Hi SFisher,

welcome to the forum! To be honest, I don't believe that somebody in this forum has installed exactly this sensor. There are far to many items available at Aliexpress, but for less than 3€ it might be worth to give it a try. Delivery time for that item is indicated with 2 months to Germany which is quite long, but feedback from other buyers is not too bad. It might be suitable to detect movements in a close distance rather than presence with a higher distance, so I believe that it might work in the use case you've described.

Such a PIR sensor does not produce an analogue output, but a digital one. If motion (to be exactly it's the body heat) is detected, the output is switched on for a specific duration. So you need a digital input on the Loxone side and that input would not require any voltage conversion if you power the PIR directly from you Loxone 24V DC power supply. If you don't have a DI left, but only an AI, then you might build a voltage divider, see https://en.wikipedia.org/wiki/Voltage_divider that converts 24V to 10V. You just need to do some simple maths or use an online calculator and 2 resistors to build such an converter. You may also buy a DC to DC converter (step down buck) to do that job, but in my opinion that's too much.

EDIT: I just had a look into the data sheet for the AI extension. It looks that this extension allows digital signals up to +25V, so you may skip the power conversion.

Cheers,
Jan

[SFisher]

Hello, Jan W., thank you for your feedback and sorry for my late response.
I'm going to power this sensor from another power supply. I'm planning to have Dimmer Extensions with extra power supply and use it for sensors too, because they will be located out of main loxone system box.
Do you think it can cause an issue?
Thanks

[Jan W.]

You need to connect ground of affected power supplies with a thick wire to provide the same level.

[SFisher]

OK I see thanks - It will be problematic - I have AWG24 there for communication with Loxone Miniserver. So will need to do some convertors...

[querex]

https://www.loxforum.com/forum/hardware-zubeh%C3%B6r-sensorik/404249-allgemein-24v-dc-bewegung-pir

I ordered the same sensor to give it a try.
(Used similar 24v 3 wire sensors in the past, also 24v DC with a similar housing)

As the sensor has an open collector output.
You need to install a pull up resistor on the black output wire.
And in the Loxone config, you need to invert the input signal (motion = 1, no motion = 0).
Loxone open collector / pull up resistor documentation:

https://www.loxone.com/enen/kb/wiring-accessories/#CONNECTING%20OPEN%20COLLECTOR%20OUTPUTS

[SFisher]

thank you for your comment
So I should use the same 24v DC for these sensors as well as for miniserver... I'm planned to use separate 24v for it, because another box with RGBW extensions located in ~10m from the main box with miniserver...

[SFisher]

Anyone has experience to use for digital input "common ground", but separate "+" (from different DC converters)?