How to solder a usb cable directly to Arduino Mega (usb port got smashed)

I have an Arduino Mega, and the usb port got smashed pretty bad. I removed it from the board, and I has an extra USB cable. I want to cut and solder the cable directly to the arduino, Just by looking at the circuit, I can tell where the ground and +5 are, but the out of the other two, I can't figure out which is the USB data + and which is the USB data -. Does anyone know?

I would advise against that, you would be much better off soldering a new socket on it.
To identify which data line is which, look at the PCB layout and follow it back to the chip. The data sheet for the chip will show which is which.

Look at the schematic for any Arduino board, and it shows which pins on the USB
connector are what. If by "solder the cable directly to the arduino", you actually
mean solder the cable directly to the arduino, this will be a problem as you will be
interfering with the on-board voltage regulator and USB-PowerJack switching
circuitry. How about just attaching power to the Power Jack [eg, via wallwart].

all the usb port really does is connect the wires of pins, my thought was to solder each wire to the corresponding pin, I can't see how this is functionally any different than plugging the cable in. As far as soldering a new terminal on, I would like to do that but I'm in a pinch, and I need this working, don't have a new port

Oh, slight misunderstanding. You can solder to the original USB pins on the "board" ok.
You cannot solder directly to the Arduino "chip". Cut the connector off the end of the
USB cable, and it should be pretty obvious which pins are which. Something like
red-white-green-black-shield. It would help to have an ohmmeter to test continuity
to the pins on the other end, of course.

tester:
all the usb port really does is connect the wires of pins, my thought was to solder each wire to the corresponding pin, I can't see how this is functionally any different than plugging the cable in. As far as soldering a new terminal on, I would like to do that but I'm in a pinch, and I need this working, don't have a new port

Functionally it is the same but physically it is difficult. Some of the wires used in cables do not take solder well others do not take it at all. If you do manage to solder it then you have a weak point that will crack and break with only a little flexing. If you must arrange some strain relief so that the joint is not stressed.

I know this is an old thread, but I came across it on a Google search for the same thing and figured others may also, so here's what you asked for (I didn't find it so had to figure it out with an ohm meter).

I had the same problem - bad socket and no replacement on hand but needed to use the board, it was easy to do and works fine for a temp fix (may be permanent as it's just my development board so having the cord on it all the time is fine).

With the board upside down and facing you, the one closest to the board edge on the left is black, the one closest to the board edge to the right is Green, the one furthest from the board edge to the left is Red and the one furthest from the board edge to the right is White.

i.e. it looks like this:

RW
BG

(board edge)

I used a cheapie usb cable and stripped the ends and cut them short as the connections are close together and you don't want them to short out. Once soldered I taped the cable to the bottom of the board with duct tape for a strain relief.

Easy to do, works fine for a quick fix.

Steve

SLR_65:
Once soldered I taped the cable to the bottom of the board with duct tape for a strain relief.

Don't like that.

Use a "zip tie" to secure the cable to the nearby mounting hole. Preferably wrap it along the board and tie it to another mounting hole as well.

Use a "zip tie" to secure the cable to the nearby mounting hole. Preferably wrap it along the board and tie it to another mounting hole as well.

Zip ties may still allow wire wiggle. I'd use hot glue to secure the wire tightly.

zoomkat:
Zip ties may still allow wire wiggle. I'd use hot glue to secure the wire tightly.

Not if you use two zip ties through different mounting holes.

Now you speak of "wiggling", if using hot melt glue, you have to make sure it surrounds - not just attempts to stick to but surrounds a significant distance along the outer sheath of the cable to prevent it flexing at the point where the sheath is stripped and pulling loose.

Alternatively, one zip tie and hot melt glue. :grin: