# Ender 3 - v4.2.7 Board - where to plug in the BTT Smart Filament Sensor?

**URL:** <https://marlin.crc.id.au/forum/t/ender-3-v4-2-7-board-where-to-plug-in-the-btt-smart-filament-sensor/1949>\
**Category:** Support\
**Tags:** bltouch\
**Created:** [10 November 2023 06:13 UTC](https://marlin.crc.id.au/forum/t/ender-3-v4-2-7-board-where-to-plug-in-the-btt-smart-filament-sensor/1949 "2023-11-10T06:13:15Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Chris\_Jones](https://marlin.crc.id.au/forum/user_avatar/marlin.crc.id.au/chris_jones/32/1006_2.png) [@Chris\_Jones](https://marlin.crc.id.au/forum/u/Chris_Jones)\
**Post date:** [10 November 2023 06:13 UTC](https://marlin.crc.id.au/forum/t/ender-3-v4-2-7-board-where-to-plug-in-the-btt-smart-filament-sensor/1949/1 "2023-11-10T06:13:15Z")

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After my board shorted due to a Thermal Runaway E1, I’ve downloaded the latest firmware and because I saw that Smart Filament Runout Sensor had been enabled. After clicking that link and being wowed, I ordered one from Amazon. The BIGTREETECH BTT SFS V2.0 Smart Filament Sensor.  
It’s a four wire sensor rather than the regular 3 wire, so I guess I can’t use the regular port on the 4.2.7 board.

Where do I plug it in?  
Thanks so much! This site is a wonderful resource and well worth the subscription of fifteen dollaridoos 🙂

Chris

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**Author:** ![Calvin\_Love](https://marlin.crc.id.au/forum/user_avatar/marlin.crc.id.au/calvin_love/32/1178_2.png) [@Calvin\_Love](https://marlin.crc.id.au/forum/u/Calvin_Love)\
**Post date:** [17 August 2024 17:39 UTC](https://marlin.crc.id.au/forum/t/ender-3-v4-2-7-board-where-to-plug-in-the-btt-smart-filament-sensor/1949/2 "2024-08-17T17:39:29Z")

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Did you ever get this goin? I’m honestly astounded how hard getting 3d printer upgrades in ends up being.