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After seeing some youtube videos, I wanted to reuse an old laptop webcam and solder it to a USB cable.

This one comes from an ASUS X301A and looks like this: webcam

AFAIK, The USB cable needs 4 wirings: VCC, ground, data+, and data-.

This webcam shows 5 wires, which I tried to identify. Red and brown wires were twisted together. I believe that I can guess data+ and data-, with no major risk for the camera, but VCC and ground should be strictly identified.

I will refer to 3 components:

  • the ground ring
  • the 4-pins component on top of it (A)
  • the 2-pins component with plus and minus signs (B)

With a multimeter on beep mode, here are the wirings that I identified:

  • Both orange and yellow wires are connected to ground
  • A pins top-right and bottom-right, and of course B-, are connected to the ground
  • The brown wire is connected to top-left A pin
  • The red wire is connected to bottom-left A pin

My problem is that I could not identify any pin connected to the black wire or to B+. Moreover, the fact that 2 wires are connected to the ground looks a bit strange to me (why use 2 wires?).

Therefore, I am very confused about which wire to connect to the USB cable.

Based on this, is there a way I could identify which is which?

EDIT

As @Justme said in comments, beep mode is not sufficient, so here are the actual resistance values (2k ohms):

Multimeter's red on component, black on wire:

+--------+--------+------+------+------+------+------+
|        | ground |  A+  | Btl  | Btr  | Bbl  | Bbr  |
+--------+--------+------+------+------+------+------+
| black  |   0,42 | 0,89 | 0,47 | 0,47 | 0,47 | 0,47 |
| brown  |   0,42 | inf  | 0    | 0,64 | inf  | 0,64 |
| red    |    0,6 | inf  | inf  | 0,64 | 0    | 0,64 |
| orange |      0 | inf  | 0,85 |    0 | 1,5  |    0 |
| yellow |      0 | inf  | 0,85 |    0 | 1,5  |    0 |
+--------+--------+------+------+------+------+------+

Multimeter's black on component, red on wire:

+--------+--------+-------+------+------+------+------+
|        | ground |  A+   | Btl  | Btr  | Bbl  | Bbr  |
+--------+--------+-------+------+------+------+------+
| black  |    1,1 | inf   | inf  | 1,08 | inf  | 1,08 |
| brown  |   1,46 | inf   | 0    | 1,46 | 1,66 | 1,46 |
| red    |    1,5 | inf   | 1,67 | 1,46 | 0    | 1,46 |
| orange |      0 | 0,878 | 0,64 |    0 | 0,64 |    0 |
| yellow |      0 | 0,878 | 0,64 |    0 | 0,64 |    0 |
+--------+--------+-------+------+------+------+------+
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    \$\begingroup\$ You can't reliably use beep mode to blindly figure out which is which. It will beep if the measured resistance is below some threshold and not beep if measured resistance is above some threshold. It may fail to beep if there is large enough resistance, and it may beep if there is enough load or just capacitance or protection diodes. \$\endgroup\$ – Justme Jun 5 at 14:01
  • \$\begingroup\$ @Justme Thanks, this is very true. Here are the actual resistance values. Based on them, it would make me think of Black=VCC, orange+yellow=GND, and brown/red=data+/-. Does this seem right to you? \$\endgroup\$ – Dan Chaltiel Jun 6 at 6:24
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Finally, it worked!

  • orange & yellow=GND
  • Black=VCC
  • brown=data+
  • red=data-
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