I want to connect my android phone and arduino to create a fast and reliable serial connection. I've read that it is possible with USB OTG but i will need to charge my phone eventually. So i was wondering if i can use another USB cable to feed VCC for both cables while maintaining data connection between arduino and android. I created this simple schematic. Will this work for what i wanted to do? (Sorry for mistakes. English is not my native language.)

External VCC for 2 USB Cables


  • \$\begingroup\$ Who is USB master and who is USB slave in your schematics? Also, modern smartphones have micro-B connectors, which have extra ID pin. Where is it in your schematics? \$\endgroup\$ Commented Mar 30, 2019 at 21:05
  • \$\begingroup\$ @Ale..chenski android will be the master and arduino will be the slave. I planned this as a board where i can connect 3 usb cables this is why i added 3 USB-A connectors. In this case do i need id pin? \$\endgroup\$
    – Montrama
    Commented Mar 30, 2019 at 21:11
  • \$\begingroup\$ ID Pin is used with OTG to determine who will be host side of USB and who will be device side of USB. You should read up about this from numerous web pages. As long as the Android phone is in host side role most phones cannot be charged as the host side is supplying the USB V+. \$\endgroup\$ Commented Mar 30, 2019 at 21:15
  • \$\begingroup\$ @MichaelKaras Now i'm on right path. I knew it can't be this easy. \$\endgroup\$
    – Montrama
    Commented Mar 30, 2019 at 21:17

1 Answer 1


No, this won't work. You need to make or buy so-called "accessory charger adapter", or "ACA". Here is the correct arrangement:

enter image description here

It might be though that your smartphone doesn't support this ACA arrangement, this method is old.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.