I wanted to create a cellphone holder for my bike and use my cellphone as a bike computer.
I make it from scratch thanks to 3D modelisation on Fusion 360, then I printed pieces on my 3D printer (Alfawise U30).
To keep my bike safe, I use O-ring between my bike and the cellphone holder. It works good but I have to improve pieces which allow to pick up the cellphone from the holder.