# Detect a negative edge

**URL:** <https://community.homey.app/t/detect-a-negative-edge/81125>\
**Category:** Questions & Help\
**Tags:** flow, homey-pro\
**Created:** [May 25, 2023, 10:38am UTC](https://community.homey.app/t/detect-a-negative-edge/81125 "2023-05-25T10:38:33Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![GeeGee](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/geegee/32/71446_2.png) [@GeeGee](https://community.homey.app/u/GeeGee)\
**Post date:** [May 25, 2023, 10:38am UTC](https://community.homey.app/t/detect-a-negative-edge/81125/1 "2023-05-25T10:38:33Z")

</div>

How can I detect a negative edge?  
I would need it to detect a negative edge from smart detection of a camera. This to reset in case it’s just a glitch. I would like to trigger an alarm only after x seconds.  
Thx