USB Condom (XS snug fit)

thingiverse

A USB Protector is designed to safeguard your devices when charging from untrusted power sources, such as a stranger's computer or an unknown outlet. This necessity arises because unsecured I/O connections can enable malicious parties to access and manipulate your device without consent. Using this protector also secures the safety of your computer by preventing unauthorized access via its USB ports. When someone wants to charge their device from your computer, this protection ensures that they cannot compromise your system. My primary objective was to create a compact yet robust design that is simple to print without supports. As a single-part component, it is extremely easy to assemble. If you find this protector useful, a small donation can go a long way in showing your appreciation. Here are the steps to build one: 1. Print the protective case without any support structures. 2. Cut out a 10x30mm strip from a four-trace PCB strip. 3. Solder a USB A connector onto the strip board. 4. You may need to trim off excess metal clamps or other components from the connector. 5. Install voltage dividers on your Android device, using a 100-ohm resistor between D- and D+ is sufficient. 6. Remove the inner traces except where the pins are soldered. 7. Insert the connector into the case, trim if necessary to ensure a snug fit. 8. Fill the empty space under the connector with hot glue. Note: To enable charging above 500mA, you must connect the middle traces with a 100-ohm resistor. For iPhone users, adding voltage dividers to D- and D+ is required; refer to the circuit diagram for more information. I have created two versions of this protector: one shorter and one longer. The longer version accommodates the 0.25W resistors needed for voltage dividers. Warning: Do not use the variant with voltage dividers to charge your device from a standard USB port on a computer, as these are rated for only 500mA. Proceed at your own risk.