Raspberry Pi USB-C Security Stick Design

Project: USB-C Security Stick (Raspberry Pi Zero 2W Based)
Overview

I want to create a USB-C security stick that functions in two modes:

Cable Mode (Personal Firewall)

Plug into a laptop/PC via USB-C.

Device acts as a firewall (via USB Ethernet Gadget).

Filters/block traffic (e.g., only allow HTTPS, block malicious sites).

Provides secure payment browsing and optional VPN tunneling.

Router Mode (Home Firewall & Parental Controls)

Connect device to home router or modem.

Acts as a mini-firewall and DNS filter for the entire household.

Parental controls via mobile app:

Block unwanted sites (gambling, adult, TikTok, YouTube, etc.).

Allow internet for limited time (e.g., 30 mins).

Device/user profiles (e.g., child vs parent access).

The stick should be fully controlled via a mobile app (iOS + Android).

Goals

Develop a working prototype on Raspberry Pi Zero 2W (later custom PCB).

Secure network filtering in both modes.

Mobile app (React Native preferred) to control settings.

Simple consumer-friendly design (later stage: 3D-printed or injection-molded enclosure).


Required Features
Cable Mode

Pi Zero 2W acts as USB Ethernet Gadget.

All laptop traffic routed through Pi.

Firewall filters (iptables/nftables).

Optional VPN or TOR tunneling.

Router Mode

Pi Zero 2W acts as WiFi AP or sits between router & internet.

DNS filtering (Pi-hole or AdGuard Home).

Site blocking (adult, gambling, social media).

Device profiles + timed access.

Mobile App

React Native app (iOS + Android).

Connect to Pi API (via REST/HTTPS or WebSocket).

Features:

Toggle Cable/Router mode.

Manage blocklists.

Create usage schedules.

View activity logs.

Tech Stack (Suggested)

Hardware: Raspberry Pi Zero 2W, USB-C OTG support.

OS: OpenWrt or Raspberry Pi OS Lite.

Networking: iptables/nftables, dnsmasq, Pi-hole/AdGuard.

Backend on Pi: Python (Flask/FastAPI) or Node.js.

Mobile App: React Native.

Database: MongoDB for storing rules & logs.

Deliverables

Prototype software running on Pi Zero 2W.

USB-C Cable Mode Firewall (PC sees Pi as USB Ethernet card).

Router Mode Firewall (with DNS filtering & parental controls).

Mobile App (basic UI to control filters & schedules).

Documentation for setup & usage.

Required Skills

Embedded Linux (OpenWrt / Raspberry Pi OS).

Firewall & DNS filtering (iptables, nftables, Pi-hole, AdGuard).

USB Gadget development (Ethernet over USB).

Mobile app development (React Native).

API design (REST/HTTPS, WebSockets).

PCB design experience (future phase).

Project Phases

Phase 1: USB Ethernet Gadget + firewall rules on Pi.

Phase 2: Router mode with DNS filtering.

Phase 3: Mobile app integration (basic control).

Phase 4: Advanced parental controls (timers, device profiles).

Phase 5: Prototype enclosure (3D printed).

This project is ideal for someone experienced in embedded Linux, networking, and mobile apps with react native who can integrate everything into a consumer-friendly prototype.