How To Build A USB OTG Cable

How To Build A USB OTG Cable

Knowing how to make your own USB OTG cable can be very useful to you. The purpose of USB OTG (On-The-Go) is to allow you to connect and use standard USB input devices like flash drives, keyboards, computer mice, and game controllers on mobile devices such as a smartphone or tablet computer. With so many varying connectors to mobile devices however, it’s sometimes hard to find the right USB OTG cable, if one even exists at all.

Many premium smartphones and tablets today support USB OTG (On-The-Go). This interface allows you to connect USB gadgets to these mobile devices and interact with them. For example, you could open and view files saved on a USB drive or browse through your phone’s operating system with a computer mouse.

The problem however, is that very little of these mobile devices (if any) come equipped with a compatible USB host port. Some smartphone manufacturers sell USB host ports with their handsets while others have them as optional accessories, usually sold at a high-end price.

To connect a mobile device to a standard USB input device, you need to use a micro USB to USB Type A female convertor, but this should also be an OTG cable. Mini USB OTG cables are available for a relatively fair price, but finding actual vendors who will sell them is not as easy. The ones that are available are not actually guaranteed to work, and the case is the same with Micro USB OTG cables.

For this tutorial, we’ll walk you through how to make your own OTG cable at little to no cost. Keep in mind however that the process could potentially damage you existing usb cables and even possibly the mobile device you use with it. Follow this tutorial with extreme caution as we will take no responsibility for any damages to yourself or your devices.

Before you proceed, also make sure that your mobile device can actually support OTG capabilities. Mobile phones with third party developer ROMs installed should check with the developers if the USB OTG feature is enabled on the kernel. Since most phones ship with cables, I suggest that you use a secondary one you purchase online for the USB OTG cable. If you’re not able to find a similar cable, this tutorial will walk you through how to use the original cable for regular and OTG modes. In the following tutorial, we will be using a Micro USB cable that we are going to convert to be used with USB OTG on an Android smartphone device.

Things You’ll Need:

  • A knife
  • Hot glue
  • Small, thin wire
  • Soldering iron and solder wire
  • A standard Micro USB Cable
  • Wire cutter


Slice open the Micro USB connector end very carefully using your knife. What you need to do is cut (length-wise) the outer sleeve into two halves to reveal the connector inside. Be careful not to destroy the outer sleeve as you’ll be gluing it back on after all your work is done.

After you’ve taken the sleeve apart, some of you might find a whitish plastic mould covering the connector’s leads, This mould is for strengthening the cable to connector contacts, and its use depends from manufacturer to manufacturer. If you see this whitish mould, cut through it carefully to reveal the connector leads for the Micro USB cable. You’ll notice that the cable has five leads. The five leads are: power, data (negative and positive), data and ground, while the last, non-connected lead is sense. This last lead needs to be grounded before connecting the cable for the phone to switch to OTG mode and sense a USB device connected to the interface.

Above is a “Pin-Out” diagram for the micro and mini USB connector.

Pin 1: VCC

Pin 2: data

Pin 3: data

Pin 4 Not connected / unused

Pin 5: ground

To get the phone to go into USB OTG mode, you’ll need to short Pins 4 and 5. You can either choose to short them permanently by soldering them together or soldering two wires to each of the pins and leading those outwards from the connector, which can then be soldered to a small switch.

With a switch, you can change the cable from normal to OTG whenever you want. If you choose to short it permanently, then you’ll have to cut off the connector at the other end and solder a Type B Female connector to accommodate a USB device. You can also choose to have a male to female USB convertor at the end.

For the purposes of this tutorial, let’s go with the switch option. This way, you’ll be able to use the USB OTG cable for both regular and OTG purposes. Glue the connector sleeves back carefully using hot glue. On the other end of the cable, (the one with the male USB Type A connector), you’ll have to change that up into a female connector. We used a scrapped USB rear panel connector of a desktop PC for the job, but you can also use an old USB hub port as well. Lastly, solder the wires of the USB connector to create the USB female to female convertor. This is your standard OTG cable.

Make sure your check for any cable shortings during soldering with a multimeter device. Once it looks like everything’s all clear go ahead and plug your phone in and check if it works with any of your basic USB devices like a keyboard or mouse.

How’d everything go for you? If you have any additional questions or would just like to drop us some feedback, please leave a comment below.

Vincent Clarke

Vincent Clarke is the Universal Serial Bus (USB) Guru for When he's not writing tutorials and catching up on the latest USB news, Vincent is busy preparing his next blog post and answering USB questions from his readers and subscribers.

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