This project is about adding an USART (and optionally Bluetooth) interface to a kitchen scale. This is done by measuring a PWM duty cycle if a ramp-compare ADC in the scale. The PWM duty cycle is directly (or within acceptable margin of error) proportional to the applied weight.
You can read more here: http://adam-dej.github.io/2014/07/08/scale-interface.html
Scale with a ramp-compare ADC with accessible PWM pin