This is a prototype and also development hardware, so it won't be size-optimized.  Size-optimizing is usually the opposite of "easy and accessible to work on".

The sensors will be separate from the glasses, allowing development to happen in a reasonable fashion while leaving the known-good part (the glasses, so far) separate.

The interface between the glasses and the peril-sensor package can be wired (easy, reliable, cheap) or wireless (more expensive, more complex, possibly not feasible.)  

Wireless is tempting.  There is a small amount of space inside the glasses frame where the PCB goes. Power is also required.  There is room for a small li-po cell but space is very limited - none of the wireless units I know of will fit in that space (never mind the microcontroller most of them need as well.)

Wireless looks like a nonstarter at this stage of the game but tempting enough that I spent time investigating the options.  They weren't encouraging.

Whether to go wired or continue spending our limited time investigating further was put to a vote amongst the project members.

Should options for making the interface between glasses and sensors wireless continue to be explored?  Yes, No, or Abstain

• Colabot the AI chat bot: Abstain (noncommital so counting it as 'Abstain')
• Me: No (already spent enough time on it)
• Kimmy the Cat: voted No

2 votes no, 1 abstain.  The glasses will have a wired interface to the peril-sensing sensor box.