[Pete] was building a hot tub controller, using a WEMOS board based on the venerable ESP8266. After assembly, the board was plugged into USB and [Pete] hit the flash button. No dice. Investigation … ...

To configure the ESP8266, [dequng] is using the ESP-TOUCH app for Android, and setting up new functionality in this ESP button is as simple as putting a URL in the button’s Flash.

Twenty bucks for a good fitness tracker, and more: the Misfit Flash Link can be a selfie or music remote. And Misfit's dropped prices on its other trackers, too.