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.

2 thoughts on “
This 6X USB charger has a current monitor

  1. frank26080115

    Is this really an official Atmel blog? Or is it unofficial?

    Thanks for posting my project. I’ve got projects on my site dating back several years and 80% of them involve AVR.



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