I want to keep the physical design simple and accomplish two main goals: protect the sensors and circulate air. I ended up using an enclosure I had on-hand that could easily be modified to meet these criteria.
The board, battery and all cables fit easily inside a 1.5″ x 2.5″ x 4.5″ metal “stomp box”. This is a common and cheap (about $5) enclosure used by musicians to mount buttons that can be activated by foot on stage. I drilled a number of small holes in the box on one end near the sensors and on the top on the other where I mounted the fan. This enclosure will then be connected by a short cable to a separate enclosure for the LinkIT ONE.
Here are a few photos that show what the final physical design looks like.