@Satur9 perpendicular is definitely viable ^. Plus these are tiny receivers compared to the ring in the op.
For ref: https://a.aliexpress.com/_Eyv7b2Z
I had some coin shaped ones but I think I lost them , they were bright like an average flashlight and smaller in diameter than the ring here.
The coin shaped ones: https://a.aliexpress.com/_EywTCTJ