# Alternate registration? **URL:** \ **Category:** Machine Design\ **Created:** [January 20, 2021, 10:38am UTC](https://forums.kinograph.cc/t/alternate-registration/1952 "2021-01-20T10:38:13Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![patcooper](https://forums.kinograph.cc/user_avatar/forums.kinograph.cc/patcooper/32/1310_2.png) [@patcooper](https://forums.kinograph.cc/u/patcooper)\ **Post date:** [January 20, 2021, 10:38am UTC](https://forums.kinograph.cc/t/alternate-registration/1952/1 "2021-01-20T10:38:13Z")
Having now stared at my Pi monitor for several days it occurred to me that it may be possible to use a monitor for registration. My poor quality image shows a device that fits onto the front of a monitor and uses an optical sensor to detect transition from white to black. The sensor position can be varied and positioned in the best place for damaged sprocket holes. I am assuming that film with a clear base will still produce a shadow line at the sprocket hole which can be detected. ![screenframe 1](https://forums.kinograph.cc/uploads/default/original/2X/e/e3c9d7b8375645532282b1b1acfe986155dce042.jpeg) ---
**Author:** ![matthewepler](https://forums.kinograph.cc/user_avatar/forums.kinograph.cc/matthewepler/32/919_2.png) [@matthewepler](https://forums.kinograph.cc/u/matthewepler)\ **Post date:** [January 22, 2021, 1:19am UTC](https://forums.kinograph.cc/t/alternate-registration/1952/2 "2021-01-22T01:19:19Z")
Nice hack. I hadn’t thought of that one. Any luck? ---
**Author:** ![patcooper](https://forums.kinograph.cc/user_avatar/forums.kinograph.cc/patcooper/32/1310_2.png) [@patcooper](https://forums.kinograph.cc/u/patcooper)\ **Post date:** [January 22, 2021, 9:43am UTC](https://forums.kinograph.cc/t/alternate-registration/1952/3 "2021-01-22T09:43:45Z")
Cheers, Just getting components, should have a trial ready over the weekend