Saturday 4 April 2015

TecSupply, a 5$ OTG-Charging cable for Teclast tablets

Today, we are going to make the TecSupply, a 5$ essential accessory for Teclast tablets.

If you purchase a Teclast tablet with the purpose to be productive and to work under Windows, this accessory makes the difference to extend working hours beyond the battery life. For example, in case of a X98 3G you have a good battery life for sure with 8500mAh, but with an intensive working activity (or a device connected with Teclast OTG cable) is impossible to keep your tablet over 7 hours.

There is an switchable usb hub you can purchase online in cinese stores, but it's more expensive than our project and maybe you prefer to use your old usb hub hidden at the bottom of drawer.

With some dollar, you can make this project and it will work such as the hub you have read online. However, to be accurate, as we just said this accessory works as the switchable usb hub. So this means that it holds in charge your tablet, it doesn't charges literally the battery!

It has been a common error of all user that have purchased the switchable usb hub, as you can read on XDA some users have reported this bad news. Good news, this clarification has helped us to design our project properly for these tablets.

The circuit is shown in the picture below.

Its very simple, it's composed of three usb ports and a notification led, plus other components to supply the cable with an external power supply. The power plug, the fuse and the diode haven't been mounted, we have prefered to use only usb plugs to power the device.

If you prefer an external power supply, this should have an output of 5v and 2.5A, the fuse (of 2.5A at the same way) protect the circuit from overcurrent and the diode from polar inversion. The last component is an header that exclude every external supply, only used for circuital test.

How does it work?

First of all shut down the tablet, then connect the usb cable of Teclast and another usb cable male-to-male such as in the picture below. We called it "L connection".

After a while, you have to switch to "direct connection", now you can switch on the tablet to boot Windows.

After the boot and logging, you can connect the device you want, an usb hub for example.
In the video below we show a demo of this procedure, take a look if you have some difficulty.

That's all for now. Let us take advantage of this situation to wish you Happy Easter.

Keep in touch with us for new useful projects and you don't forgotten to download our application from Google Play.

Have a nice Easter.

Files on git.


  1. Thank you for sharing this information and Very good looking blog on otg cable

  2. So, using thi OTG, we can connect Keyboard and Mouse meanwhile changing x98 Air 3G?
    If yes, please share purchase link..

  3. This is actually the kind of information I have been trying to find. Thank you for writing this information.


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