This 6X USB charger has a current monitor

Frank Zhao, an electrical engineer and DIY hobbyist, has designed a simple 6 port USB device charger with an individual current monitor on each port.

“The problem I faced was that I had too many devices to recharge at once, not having enough chargers and not having enough AC jacks,” Zhao explained in a recent blog post.

“Also my new Sony wireless headset was being picky about both the cable I use and the charger I use. I decided to troubleshoot this problem by building this tool.”

Key project specs include Atmel’s versatile ATmega328P microcontroller (MCU), an INA169 breakout board and an OKR-T10-W12.

The charging current is indicated using RGB LEDs. More specifically, blue means slow charge (under 250mA), green 250mA-750mA, red over 750mA and purple over 1500mA (for tablets).

“Wiring is done using 30 gauge Kynar coated wire. A decently capable wall-wart is needed, anywhere between 4.5V to 12V is acceptable and it must be able to supply enough current for all the devices to be charged,” Zhao continued.

“A DC/DC converter is used to increase efficiency, so a 12V wall-wart supplying 4A can actually charge about 8A total. The D+ and D- signals have the appropriate resistors to enable high charging rates on Apple devices – which is compatible with Sony, Samsung and other brands.”

Zhao also noted that he deliberately omitted a number of features from his charger due to cost and time constraints, including reverse polarity protection, input fuse, individual over-current cutoff and LED dimming.

Interested in learning more? You can check out the project’s official page here.