[Aleksejs Mirnijs] needed a tool to accurately measure the power consumption of his Raspberry Pi and Arduino projects, which is an important parameter for dimensioning adequate power supplies and battery packs. Since most SBC projects require a USB hub anyway, he designed a smart, WiFi-enabled 4-port USB hub that is also a power meter – his entry for this year’s Hackaday Prize.
[Aleksejs’s] design is based on the FE1.1s 4-port USB 2.0 hub controller, with two additional ports for charging. Each port features an LT6106 current sensor and a power MOSFET to individually switch devices on and off as required. An Atmega32L monitors the bus voltage and current draw, switches the ports and talks to an ESP8266 module for WiFi connectivity. The supercharged hub also features a display, which lets you read the measured current and power consumption at a glance.
Unlike most cheap hubs out there, [Aleksejs’s] hub has a properly designed power path. If an external power supply is present, an onboard buck converter actively regulates the bus voltage while a power path controller safely disconnects the host’s power line. Although the first prototype is are already up and running, this project is still under heavy development. We’re curious to see the announced updates, which include a 2.2″ touchscreen and a 3D-printable enclosure.




[Befi] wanted to add a second stage backup disk to his ODROID embedded-board server, which typically draws ~1.5W at idle. After adding the disk, he saw power consumption increase by 2W when the new disk wasn’t spinning. He thought about using one of those USB hubs with the adorable little rocker switches for each port and replacing them with transistors, but that was going to be messy. After some poking around in the USB standard, he found that most support per-port power switching (PPPS), and set about to 

