Everyone have at least couple devices that can be charged via USB port. These can be cell phones, tablets, or media players. There is no problem with one device or two. But when you have to charge several at once, you get pretty messy with wires and chargers. Frank decided to fight this problem by building six port USB charger with current monitor feature.
Charger is driven by Atmega328p microcontroller which interfaces six INA169 current shunt monitors. Each USB charging port is paired with RGB LED where different color indicates different charging current. Blue is for slow charge (250mA), green indicates up to 750mA current, red is up to 1500mA and purple glows when current is over 1500mA. Charger needs to provide high current if all ports are busy. There is a 10A DC/DC converter module OKR-T/10-W12-C used. There could be further improvements to this circuit like reverse polarity protection and over-current cut-off.