@popsyann said in Battery life for Motion Sensor: When I load the motion sensor sketch, it start properly, finding the right "parent" and immediately after this, there is a flow of info going out of the Arduino+sensor, sending 0s or 1s, constantly (like if there was an issue with the interrupt process). And what I do not understand is that this (these) sensor(s) has(have) been working well for a while. Please search for sleep() function - it has changed the way it works at some stage in MySensors 2.* https://forum.mysensors.org/topic/1088/battery-powered-pir https://forum.mysensors.org/topic/5807/interrupt-and-sleep/26 https://forum.mysensors.org/topic/5552/pin-change-interrupt-not-firing-with-mysensors/28 Another reason could you that your PIR is not settling properly - this is why it sends out 1s and 0s to the GW. Try to insert sleep(20000); into void setup() at the end to settle the PIR