This summer, during stay in NY, I bought Qi charging circuit and receiver at tinkersphere, but until today I did not touch it. This morning, I briefly check its performance and understand how it is useful and easy to handle. I quickly order at amazon for charging station and receiver patch for some smartphone, and.. excellent Amazon.co.jp delivers my afternoon order in the same evening...! (two patches and station are less than 1000JPY..!)

This is the charging receiver. Before wiring it with my circuit, I check basic specification.

On the top of charing unit, it provides around 5V. Wonderful!

Moreover, electrodes are isolated, means it can be inserted parallel to USB 5V! Just wiring + and - to USB 5V and GND, leading...

Now my prototype "colour coded" watch has a wireless Qi battery charing function!