There is no better way to learn electronics and wearables than building your own things. The LED Breath Stats Mask is all about building a mask that displays your breathing stats. For this project, an Adafruit’s CCS811 gas sensor was used with two NeoPixel Sticks and a Circuit Playground Express.
The sensor’s Total Volatile Organic Compound monitoring is useful for detecting acetone levels on the breath and determining whether you are burning glucose or fat. The instructions are available here.