It uses an unmodified Ruuvi tag, factory installed firmware and uses RuuviCollector to update an influx database running on RuuviBerry installed on a Rasperberry Pi Zero W!
The Ruuvi includes an X-Y-Z accelerometer. When the tag is not moving, the Z component reflects the orientation of the tag. See previous discussion Garage Door Monitor
Attaching a Ruuvi tag to the door frame with a piece of double-sided mounting tape allows the tag to tilt based on the door position.
2020-02-14T17:27:10.359970873-05:00 -0.164 -. 2020-02-14T17:27:19.295948153-05:00 -0.16 | 2020-02-14T17:27:31.338883754-05:00 -0.144 | 2020-02-14T17:27:43.376029198-05:00 -0.096 | 2020-02-14T17:27:52.356238751-05:00 -0.048 | 2020-02-14T17:28:04.364938067-05:00 -0.02 | opening 2020-02-14T17:28:13.37577315 -05:00 0.112 | 2020-02-14T17:28:22.364090296-05:00 0.124 | 2020-02-14T17:28:34.336402424-05:00 0.264 | 2020-02-14T17:28:43.418743646-05:00 0.352 | 2020-02-14T17:28:55.362867678-05:00 0.524 | 2020-02-14T17:29:04.347345399-05:00 0.608 | 2020-02-14T17:29:16.322086916-05:00 0.732 | 2020-02-14T17:29:25.367256974-05:00 0.82 | 2020-02-14T17:29:37.303493498-05:00 0.872 -' max open 2020-02-14T17:29:46.307488655-05:00 0.864 =. 2020-02-14T17:29:55.303799785-05:00 0.776 } 2020-02-14T17:30:07.360117257-05:00 0.684 } 2020-02-14T17:30:19.29655135 -05:00 0.512 } closing 2020-02-14T17:30:28.302990531-05:00 0.368 } 2020-02-14T17:30:40.32296598 -05:00 0.212 } 2020-02-14T17:30:49.30119734 -05:00 0.088 } 2020-02-14T17:31:01.340790436-05:00 0.024 } 2020-02-14T17:31:11.214035758-05:00 -0.064 ='Perhaps one of you mechanical engineers with CAD / 3D printer skills can make up a more "professional" version.