[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.

On her blog, Dustyn Roberts presents her own experience on current sensing for controlling DC electric motors with an Arduino board and an Arduino Motor Shield. This shield, based on a L298 H-bridge, provides two current sensing pins to the user, which can be used to measure the instantaneous current absorpion by each H-bridge. After some trials, Dustyn managed to have a quite clear picture of the absorption behavior of the DC motor:

Sample code and updates can be found on Dustyn’s blog.

[Via: Dustyn's blog]

Ever wanted to see how much electricity your next project is consuming? Look no further; this Instructable will guide you about how you can, too, make a device to monitor the same.

This project was developed by Steve Spence of Arduinotronics with input from forum members at the Yahoo Group - Arduino Home and The Arduino Forum.

Steve writes:

“There’s a couple of commercial products that can do this, but not with the flexibility I wanted. I designed an Arduino micro-controller based solution that is very extensible. Right now it monitors the above values of attached gear, and I’m thinking about adding web monitoring and an SD Card for data collection.”