Introduction: How to Add Separate USB Power Supply to an External Hard Drive

By Visit My Youtube Channel
About: Not much to say, just another guy who likes to build electronic stuff

Hi guys, in this video we will see how to make a Y splitter cable that divides the 5V power supply of, for example, an external Hard Disk and the data.

Have you ever installed a heavy game on an external hard drive?

If yes, you know that when the game requires too much data from the hard disk, it disconnects.

The Hard Disk disconnects because the current required for all that data is too much compared to what the motherboard can supply and therefore, for a fraction of a second, the Hard Disk disconnects.

Thanks to the cable that we will make in this video, this won't happen again because the current required by the Hard Disk will come from another USB socket that we can connect to a wall adapter or any external power supply.

Supplies

  • USB cable to split
  • Another USB cable (cut or to be cut)
  • Insulating tape
  • Heat shrink tubing
  • Cloth Tape (American Tape)

Step 1: Prepare the Power Cable

First of all, you will have to provide yourself with a normal USB that you do not need or that is broken or cut.

Once you have found the cable, if it is intact, you will have to cut and strip it to detect inside (if it is a standard USB cable) four colored wires of the following colours: White, Green, Red and Black.

Of these four wires, the only ones you will need are those carrying the negative (therefore the GND) and the positive (therefore the 5V). These are the Red and Black threads (as it was easy to guess). You can then take a pair of scissors and cut the Green and White threads (so you can wash them afterward).

Once this is done, you have to check that the cable works correctly and that there is voltage at the ends of the red and black cables.

You can connect the cable to the computer and measure the voltage, but I don't recommend it (because you could damage the computer if you short-circuit). Rather, take a phone charger and insert the USB into it (which surely is protected from short circuit and surely would be damaged less than a computer and certainly less expensive than a computer).

Once the USB socket is connected to the charger, insert it into the socket and, with a digital multimeter, measure the voltage across the Red and Black wires. The value should be around 5V (in this case, 4.99 )

Step 2: Strip the Main Wire

It's time to move on to the other cable, the main one, the one that will be connected to the Hard disk or I don't know what.

You will have to peel the latter using a very sharp cutter and in this position. You will need to apply a little pressure, at a small angle, on the cable jacket and sooner or later you will start to feel that you are cutting through the jacket.

When you start to feel something harder, stop, you've reached the metal mesh (which protects the wires from interference).

Repeat this process on multiple sides of the cable so you don't have to strip the jacket.

When that small portion of cable is totally free from the sheath, cut the metal mesh with a pair of scissors and then cut the last layer of protection from interference, made from a thin sheet of metal.

Step 3: Locate the Positive and Negative on the Main Cable

At this point, as with the cable above, we need to locate the red (positive) wire and the black (negative) wire inside the cable.

To these then, we will have to weld in parallel the red and black wires previously identified in the other cable, the power supply one.

Step 4: Strip the Power Wires Without Cutting Them

What we have to do now, in fact, is to try to strip the red and black wires of the main cable, without cutting them. For this, I first of all interleaved a piece of metal tape between the affected wire and the others, so that I didn't risk cutting the others unintentionally.

At this point, as we did before, we now have to pass the blade of the cutter over the red wire in order to slowly detect the copper underneath.

by doing so, we will be able to bare the copper of the wire without cutting it. The result should be something like this

Step 5: Do the Previous Operation Also for the Black Wire

Well, stripped the red wire, we just have to do the same thing with the black wire. This time I put my finger in place of the piece of metal. mmhh...for the record, I still have the finger. Again, the result should be something like this

Step 6: Prepare the Wires for Soldering

Good. At this point, we just have to prepare the wires for welding.

To do this, I take the red and black wires of the power cable and cut them just three millimeters, just enough for a drop of tin.

Once this is done, with the tip of the soldering iron, wet the wires with tin so that later it will be easier to solder them to the wires of the main cable.

Step 7: Solder the Negative Wires Together

Good. At this point, there is nothing left to do but wet the black wire of the main cable with a drop of tin and, subsequently, take the black wire of the power cable and solder it together with the black wire of the main cable.

The result should be something like this (photo)

Next, it is important that you insulate this weld with plenty of electrical tape.

Step 8: Do the Same for the Red Thread

Once this operation has been carried out for the two black wires, you will have to repeat it for the black wires. This therefore includes: soldering the red wire of the main cable, soldering the two red wires together and insulating the latter with electrical tape.

Step 9: Stretch the Heat Shrink Tubing

Since we have not cut the main cable but we have only stripped the wires a little bit inside, to insert a heat-shrinking sheath on the cable, we have to find a way to pass it through the USB connector which, through which, as you can see, does not pass.

Fortunately, two things come to our rescue: the elasticity of these sheaths and a thick caliper. With this, all we have to do is insert its tips inside the sheath and widen them in order to widen the sheath.

Once this is done, as if by magic, the sheath will enter the USB connector.

Step 10: Reinforce the Notch

Once the sheath has widened, insert it inside the cable and then cover the notch with a piece of duct tape (or American tape) with which we wrap the entire stripped part of the cable. This tape, being very strong, will give stiffness to the welds.

Step 11: Let's Cover the Carving

Good. Now we insert the sheath inserted before over the welds and over the duct tape.

Once this is done, we shrink the sheath with a lighter and, when the sheath is still hot, we press on it while rolling it on the table. This operation will help the sheath take the shape of the cable.

Step 12: Test

Once you've isolated everything, it's time to test that everything works. In theory, you'll need to connect one end of the main cable to your computer and the other end to a 5V supply which in my case, came from a phone charger.

The computer should read the hard disk smoothly and without errors. If we try to disconnect the Hard Disk From the computer, the Hard Disk should stay on (and in this case, a white light will shine on it)

Step 13: Finished

well, now you can go back to playing your game on the external hard drive, requesting a lot of data, without risking the hard drive shutting down because it draws too much current. See you in the next video!