This is a light weight solution to mount my "Raspberry Pi Zero - Face Camera" to an off-the-shelf helmet for use as an HMC for motion capture purposes.
For example the Brekel Body v3 app can utilize this for it's face tracking functionality.

It is fully adjustable, the mount on the side of the helmet can pivot on two axis (using a 3D printed rosette), it is held together with printed M18 bolts and can be tightened with a standard 10mm hex key or the printable key.

The camera mount can pivot on two axis and the distance of the camera to the face can be adjusted to fit your specific helmet and face.

Print settings:

All objects should be optimally oriented already, no supports needed.
Most default printer profiles (0.2mm or smaller layer height) should be fine, but it may be wise to increase wall loops and infill for increased strength.

PLA or other stiff materials are recommended so things don't flex too much.

Make sure you also print the “Case Back Bottom Rosette” from my "Raspberry Pi Zero - Face Camera" project.

Extra materials needed:

• 4x M3x16 screws and 4x M3 nuts for the rod clamps
• 4 screws and double sided tape for attaching the rosette mount to your helmet
• Carbon Fiber Rod 15mm x 300mm (12 inch)
  These are commonly used for camera rigs, you should be able to find them easily on Amazon, Aliexpress or camera stores
• A helmet (bicycle helmet, safety helmet or something similar).
  I have good experience with helmets that have a ratcheting knob at the back that allows for tightening the helmet onto your head for a snug and secure fit.

Note, the green helmet stand from the photos is this one from Phil M

Tips:

• The 15mm rod should be wide enough to route your USB cable through it
• With some double sided velcro you can attach the Powerbank to the back right of the helmet to balance everything
• A 1 meter USB cable should be long enough