The equipment to control the computer with the head mouse consists of a small self-adhesive reflector that is attached somewhere on the user’s face, an eyeglass frame, or other locations on the body, and a receiver that is positioned above the screen. In this modification the reflector is glued to a small clothespin. The reflector is larger than the clothespin, so a small plastic disc is placed under it.
Once the self-adhesive reflectors (which are expensive) are used they no longer stick and then they are easily lost. Therefore Conny glued the reflector to a small clothespin. The clothespin sits on the user’s eyeglasses. Now he can easily put it on and take it off.
Jonas, Conny’s assistant
See also spinalistips.se/en/tip-reflectors-for-controlling-head-mouse-651
This tip is from 2005.