Now my SDuino gained a bit more advanced sensing using very sophisticated sensor module (BME280) by Bosch. In general, humidity sensor is more space-taking one (as well known as BHT-11 ?) but this sensor is even smaller than general pressure/temperature sensor!

Small square metal can package is BME280, and very small means hard for hand-soldering. In my case, I just do it soldering iron as usual.

By measuring humidity, SDuino can evaluate "discomfort index" ( or temperature-humidity index) by following equation

, where T_d is temperature in deg. H is humidity in percent. Color of blinking LED will change for THI<60: blue (cold), THI<75: green (comfortable), and THI>75 (hot!).

SDuino operation does not need computer and one it is programmed, just applying 3.3 V will show you current index. This type of index is very useful to avoid heatstroke, the fatal disease in summer season!

Actual operation can be found in the following movie.. have fun!