Try @markus' new driver for the Xiaomi Mijia/Aqara motion sensor. I think it lets you reset the sensor to inactive after an arbitrary number of seconds (1-3600). I haven't tried that setting yet, but I will tonight.
EDIT: CONFIRMED@markus' new drivers let you set the inactivity timeout to anything between 1-3600 seconds and it works perfectly. No need for any hardware modification!!
Tagging @SmartHomePrimer - you might be interested in knowing this.
