DIY: USB data blocker dongle

What?

This is a quick blog on how to create a usb dongle that only allow you to charge your device without copying data.

Why?

The radio in my car accepts usb input. It have a feature that automatically detect usb and try to scan it for audio files to play.

This is a problem, as it interrupts the audio already playing when I only want to attach my phone to charge it.

How?

This is quite simple. The standard USB (1.1, 2) type A connector have 4 pins: V_bus D- D+ GND.

We have to create a new female <-> male connector that only connects V_bus & GND.

Note: fast charging won't work with this setup.

Plan

Materials required for this build

• USB Type A female socket: Either strip them or buy them from an electronics store.
• USB Type A male socket: Also widley available.
• Solder iron
• Pliers
• Shrink tubes or 3D Printer + PLA fillaments

Build steps

1. Prepare the USB Type A female/male connector.
2. Connect the male & female connectors
3. Add a case:
   • Heat shrink tubes
   • 3D Printed case

Build process

Prepare the USB Type A female/male connector

To do this, use your pliers to remove the two middle pins from the connector.

Connect the male & female connectors

Make sure you align the pins correctly. You don't want to link the V_bus to GND. The two white strips should be on opposite direction.

Add a case

This will add structural stability for your dongle.

Using heat shrink tube

I added 3 layers of the tube to give it more strength.

3D print a case

If you have access to a 3D printer you can print this model that will fit:

Voila

Do a quick test just to make sure that everything is connected correctly.