Detecting facial movements for a mask with several lighting patterns

Sensors Force & Weight
1

The mask I’m trying to build will display different lighting patterns. It is to be a portable, real-time system. The overall goal is to synchronize these patterns with a musical/dance performance, so there were two options: either hard-code the sequence in the microcontroller (https://www.sparkfun.com/products/12781) or equip the mask with one or two sensors so the change of patterns can be triggered by the wearer.

I decided to “explore” the second option first. Tracking jaw movements (how open the mouth is) and maybe the cheeks (or lips) might make it follow the speech organically. Would a Flex sensor (https://www.sparkfun.com/products/10264) be a good idea for sensing (vertical) jaw movements? Note that it is supposed to be a cloth mask, so thats why I’d like to avoid making a hinge and equipping it with a potentiometer for precise angle tracking.

Would an accelorometer work? If I were to use one, how can I prevent dancing/walking/other movement from interfering (too much)?

What could I do about tracking the cheeck/lip movent? I need only a couple of states, nothing precise. A strain sensor, perhaps?

I hope I was able to convey my question, if not please let me know

2

I can’t visualize where on the jaw/face you’d affix the flex sensor so that it will bend a significant distance and along the proper axis. Without some sort of fixturing, it would have to be glued to the skin which will probably not work so well. It would also bow in the flexed (closed mouth?) position which might push the cloth mask out.

Maybe a pressure transducer connected to a small hose the performers can blow into?

If you do go with a hinged mechanism and only need a few states, it may be easier to use a couple microswitches instead of a pot. The performer could get tactile positioning this way, too.