This is a bicycle mount for a computer and a display unit of an ebike. It has 22mm and 32mm tubes to which computers can be mounted. The mount goes into the bar end of a steering wheel. This is paraticulary useful for recumbent bikes. The mount is designed for M5 nuts and bolts, but depending on the accuracy of your 3D printer you might need to use M4 bolts. You can download the 3D files over at GrabCAD.
I created this LEGO compatible Raspberry Pi mount so that I can add it to my BrickPi robot. You can use two pins or axles to close the lock. You can download the latest version of the 3D model from Autodesk and you may need Fusion 360 to work with the file. An optimized version for for affordable 3D printers is also available. I increased the tolerances in this model. I also uploaded it to GrabCAD.