Ikea Wireless Motion Sensor - the cheapest?
Installation on the Ikea Smart Home Hub - Dirigera:
We will also add this sensor to the new Dirigera Hub. We start the Ikea APP and click on the plus sign and select "Sensor". There will be a detailed explanation. You first remove the cover at the back and insert the batteries. Now we press the pairing button on the back 4 times within 5 seconds. Please be patient because it took us more than 2 minutes until he was found.
Another small comment: it is true that the sensor does not work immediately when detecting movement. So have some patience again.