what happened to my poor dongle, behind the scene? Stealing my files? Encrypting them? Or just installing a malware? With USBvalve you can spot this out in seconds: built on super cheap off-the-shelf hardware you can quickly test any USB file system activity and understand what is going on before it's too late!

With USBvalve you can have an immediate feedback about what happen to the drive: the screen will show you if the fake filesystem built on the device is accessed, read or written:

Repository Structure

docs: documentation about the project, with a presentation where you can have a look to all the features

firmware: pre-built firmware for the Raspberry Pi Pico. You can just use these and flash them on the board. I prepared the two versions for 32 and 64 OLED versions

PCB: Gerber file if you want to print the custom PCB . It's not mandatory, you can use your own or build it on a breadboard

src: sources, if you want to modify and build the firmware by yourself

utils: some utilities you may use to build a custom FS

pitcures: images and resources used in this doc

Build USBvalve

Part list

If you want to build your own, you need:

A Raspberry Pi Pico (or another RP2040 based board, like Arduino Nano RP2040)
an I2C OLED screen 128x64 or 128x32
(optional) a USBvalve PCB or a breadboard
(optional) a 3D printed spacer to isolate the screen from the board (https://www.thingiverse.com/thing:4748043), but you can use a piece of electrical tape instead

Building instructions

Almost all the job is done directly on the board by the software, so you just need to arrange the connection with the OLED for output

With USBvalve PCB

place the Raspberry Pi Pico on the silk screen on the front
you don't need to solder all the PINs. Just the following:
- D4 and D5 (left side)
- GND (right side)
- 3v3_OUT (right side)
- the 3 DEBUG pin on the bottom: SWCLK, GND and SWDIO
place the 3D printer spacer or a piece of tape on the parts of the OLED that my touch the Raspberry
solder the OLED (with a header) on the 4 PIN space

Some of the OLEDs have the GND and VCC PINs swapped, so I built the PCB to be compatible with both versions:

For example if your OLED has GND on PIN1 and VCC on PIN2 like this:

You have to place a blob of solder on these two pads on the back of the PCB:

Otherwise you should the opposite and place the solder on the other PADs:

Without USBvalve PCB

If you are using a breadboard or just wiring, all you have to do is to ensure to connect the proper PINs at the OLED screen.

The mapping is the following:

PIN6 of Pi --> OLED SDA
PIN7 of Pi --> OLED SCL
PIN38 (GND) of Pi --> OLED GND
PIN36 (3V3OUT) of Pi --> OLED VCC

If you want to use the DEBUG functions, you can also place a header on the 3 SWD PINs at the bottom of the board.

Flash Firmware

To flash the firmware, follow these steps:

Connect the Raspberry Pi Pico with the USB cable, by keeping the BOOTSEL button pressed (the big white button on the board)
release the button
you will see a new drive on the system, named RPI-RP2 (in Linux envs you may have to manually mount it)
copy the proper firmware file (with extension uf2) in the folder, depending on the OLED you used
wait few seconds until the mounted folder disappear

It's done!

Building your firmware

Obviously you can also build your own firmware. To build the standard one I used:

Arduino IDE 2.0.4
as board I used Arduino MBED OS RP2040 version 4.0.2
Adafruit TinyUSB Library version 1.14.4. Newer versions are not working because the RPI SDK of the board is stick to an older version. May be migrate the entire project directly on Raspberry Pi Pico SDK is the solution here.
ssd1306 OLED library version 1.8.3

If you want to re-create a new fake filesystem, you may want to have a look to the utils folder, where I placed some utilities to build a new one.

NOTE: if you have ideas or improvements in your mind, I encourage you to open an issue so that we can improve the project together! Thanks!