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I want to check if a tablet or laptop has a USB-C cable plugged in so I can have a visual confirmation that it is connected correctly.

Most of the tablets I use do not have any visible feature that shows if it's plugged in or not. But even if they did, I would never be able to see it because the tablets are close together.

This is what my setup looks like:

enter image description here

When you place the tablet/laptop into the slots from the front it's difficult to tell if it made it into the connector or missed it.

My idea is to create a PCB that has 6 female USB-C inputs and 6 female USB-C outputs.

I am not sure what I need to test on the pins to determine if it's connected to something or not. I plan to use an Arduino to check the voltage and see if it drops when something is plugged in, but again, there may be a better way of checking it.

My PCB would look similar to this one, but without the headers and holes and with more than one set:

enter image description here

UPDATE 1: So something like this?

enter image description here

enter image description here

enter image description here

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    \$\begingroup\$ All the people who spent hours obsessing over their USB data track layouts are looking at that breakout board with veins popping out of their foreheads. \$\endgroup\$
    – vir
    Apr 18, 2023 at 21:15
  • \$\begingroup\$ @vir well technically I wouldn’t even need the data lines as this only needs power to charge and not data as well. \$\endgroup\$
    – StealthRT
    Apr 19, 2023 at 0:18
  • \$\begingroup\$ @StealthRT Then you don't know how USB-PD works. Disconnecting CC wires and pulling them down means you want only 5V without USB-PD communication, so the device and supply cannot communicate and many devices don't want to charge at 5V. If both ends use resistors, then you are requesting power out from device too instead of charging it. \$\endgroup\$
    – Justme
    Apr 23, 2023 at 5:53
  • \$\begingroup\$ Can you simply buy a few pieces of Type C current meters? Would likely be cheaper that trying to build any PCB and potentially having a non-working or device-damaging solution. \$\endgroup\$
    – Justme
    Apr 23, 2023 at 6:02

1 Answer 1

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The device normally will connect all gnd pins together. You could use a pull up resistor on one of the pins of the device (disconnected from the supply gnd) to sense if it is gnd or the voltage you pull it to.

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  • \$\begingroup\$ Thanks for the reply Eric. Would it be too much to ask if you could draw up a quick schematic of what you are talking about in order to give me a better idea? \$\endgroup\$
    – StealthRT
    Apr 19, 2023 at 0:16
  • \$\begingroup\$ I have updated my OP \$\endgroup\$
    – StealthRT
    Apr 23, 2023 at 2:13
  • \$\begingroup\$ That is a poor idea. Whatever charging current was passing to four ground pins would now go through only three ground pins, which means more current per pin, more voltage drop, more heating due to contact resistance. I would not recommend a downgrade like this. \$\endgroup\$
    – Justme
    Apr 23, 2023 at 5:59
  • \$\begingroup\$ @justme what would you suggest as an alternative then? \$\endgroup\$
    – StealthRT
    Apr 23, 2023 at 15:49

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