The proposed probe contains six pairs of LEDs, one photo-detector assembly and drive electronics. Each of the 12 LEDs may be selected individually, with external drive current controlling the output intensity.

The LED pairs are arranged in a circle with a 25.4mm radius.

A single flexible, multi-conductor cable provides power and control. The HDMI cable seems like a reasonable off-the-shelf solution (with mini-HDMI type C connector on the probe)

Initial (Rigid PCB) Design

• Schematic: ​PDF ​ExpressPCB
• Layout: ​ExpressPCB