Temperature and humidity measurements are a nice addition ... He decided to take an in-depth look at the DHT11 sensor; which you can get your hands on for under $3 if you know where to look.

The core of the watch is an Arduino Mini. To make it good for time telling, a real-time clock module was added. A DHT11 monitors the temperature and humidity. A charge circuit and lithium battery ...

Keyestudio’s Easy Module Shield is a learning platform for those just entering the world of Arduino and doesn’t require any soldering, making it easy to use as well. The add-on board features a DHT11 ...