“This board allows you to use a USB-C power adapter as a power supply with a range of fixed voltages. It displays a list of the voltages and currents available from the adapter and allows you to select one.
It’s based on an STUSB4500 integrated circuit and an ATtiny1604 microcontroller, and it displays the information on a 128x32 OLED display.
The original USB specification defined VBUS as a fixed 5V supply. USB-C extends this with a feature called Power Delivery. This allows a device to negotiate one of a number of fixed voltages from a USB-C Power Adapter: typically 5V, 9V, 12V, 15V, or 20V, at a current of up to 5A. It makes environmental sense, because a single USB-C power adapter can replace a multitude of different chargers for your various electrical devices.
I therefore set out to design a simple circuit that would allow you to use a USB-C power adapter as a convenient switched voltage lab power supply to power a variety of projects. It should display the voltage and current options available, and allow you to select one.”