Door/Window Sensor adhesive not good
On installation I found that every door sensor's adhesive wasn't worth a hoot. Every one of the sensors fell down thereby activating the alarm. For those sensors that I could mount to a wood surface I went ahead and screwed them into the frame. The others are sitting on metal door or window frames and had to be adjusted by using a double sided adhesive tape covering the whole back of the sensor to assure it was secure and would stay in place. Simplisafe sensors come with a very small amount of double sided adhesive that simply doesn't work. False alarms were inevitable.