# Light blocking

![](https://451694785-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MPda5vaSVRKTQ6AoAmb%2Fuploads%2Fgit-blob-14c63777db1b933b28e1f3816de088d68d01cd05%2Fimage.png?alt=media)

Slotted light barrier. The middle pin connects to + 5 V supply and the pin marked ‘-’ connects to ground. The output signal (with a 10 K ohm pullup to +5 V) is available on the pin on the right.