# PIR (motion) sensor (ADA189)
**URL:** https://forum.core-electronics.com.au/t/pir-motion-sensor-ada189/21889
**Category:** Product Questions
**Created:** [18 February 2025 01:26 UTC](https://forum.core-electronics.com.au/t/pir-motion-sensor-ada189/21889 "2025-02-18T01:26:56Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@Core](https://forum.core-electronics.com.au/u/Core)
#### Post date: [18 February 2025 01:26 UTC](https://forum.core-electronics.com.au/t/pir-motion-sensor-ada189/21889/1 "2025-02-18T01:26:56Z")
This is a placeholder topic for [**“PIR (motion) sensor”**](https://core-electronics.com.au/pir-motion-sensor.html) comments.
PIR sensors are used to detect motion from pets/humanoids from about 20 feet away (possibly works on zombies, not guaranteed). This one has an adjustable delay before…
[**Read more**](https://core-electronics.com.au/pir-motion-sensor.html)
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### Author:  [@Politas](https://forum.core-electronics.com.au/u/Politas)
#### Post date: [18 February 2025 01:26 UTC](https://forum.core-electronics.com.au/t/pir-motion-sensor-ada189/21889/2 "2025-02-18T01:26:57Z")
I have connected one of these up to a Shelly Plus Add-on, using the digital input line and a Pololu 5V Step-Up Voltage Regulator to convert the Plus Add-on’s 3.3V ref up to 5V. I am seeing constant triggering in a closed empty room. Has anyone used one of these with a Shelly Plus Add-on successfully?
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### Author:  [@Politas](https://forum.core-electronics.com.au/u/Politas)
#### Post date: [18 February 2025 01:50 UTC](https://forum.core-electronics.com.au/t/pir-motion-sensor-ada189/21889/3 "2025-02-18T01:50:55Z")
To be precise, it’s turning on and off constantly at about 1 second intervals. On for a second, off for a second, on for a second, off for a second, etc.
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### Author:  [@Dan](https://forum.core-electronics.com.au/u/Dan)
#### Post date: [18 February 2025 04:09 UTC](https://forum.core-electronics.com.au/t/pir-motion-sensor-ada189/21889/4 "2025-02-18T04:09:39Z")
Hi @Politas
If you adjust the time potentiometer does it affect the amount of time that the sensor triggers?
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### Author:  [@Politas](https://forum.core-electronics.com.au/u/Politas)
#### Post date: [18 February 2025 07:24 UTC](https://forum.core-electronics.com.au/t/pir-motion-sensor-ada189/21889/5 "2025-02-18T07:24:33Z")
Adjusting the Time trimpot seems to have stopped it triggering at all!
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### Author:  [@Robert93820](https://forum.core-electronics.com.au/u/Robert93820)
#### Post date: [18 February 2025 09:12 UTC](https://forum.core-electronics.com.au/t/pir-motion-sensor-ada189/21889/6 "2025-02-18T09:12:40Z")
Hi Politas
There is probably a sensitivity pot there as well. Could be over sensitive.
Cheers Bob
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### Author:  [@Politas](https://forum.core-electronics.com.au/u/Politas)
#### Post date: [18 February 2025 10:35 UTC](https://forum.core-electronics.com.au/t/pir-motion-sensor-ada189/21889/7 "2025-02-18T10:35:14Z")
Turns out the VREF is 10V, not 3.3V. There are some 3.3V VCC outputs I can use, though, which also allow 10mA of current, as opposed to the max 1mA of the VREF. Need to make some adjustments!
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### Author:  [@Dan](https://forum.core-electronics.com.au/u/Dan)
#### Post date: [18 February 2025 23:35 UTC](https://forum.core-electronics.com.au/t/pir-motion-sensor-ada189/21889/8 "2025-02-18T23:35:06Z")
Hey @Politas
Great to hear that you managed to work out the issue 🙂