Other (Devices, IoT & Hardware): open-source projects that exist because someone reverse engineered a closed product, sorted by GitHub stars.
Reads data from public transit cards with NFC on Android and iOS
iOS FeliCa reader for Japanese e-money, transit and ID cards
CLI and GUI that reads FeliCa transit IC cards such as Suica
Control cheap HID-based USB relay boards on Linux
NFC tag tools for Xiaomi HyperOS device linking
Third-party client for Xunlei OneThing Cloud (Wanke Yun) devices
Arduino library for low-cost LiDARs incl. Xiaomi LDS02RR, Neato XV11 and Camsense X1
Reads status from the HP DPS-1200FB server power supply over I2C
Reverse-engineered SVAKOM SL278H Bluetooth protocol with AI remote control
Python library to control Chinese USB HID 125kHz RFID readers/writers
Modified HP server PSU firmware for vehicle and charger use
Creates and removes Huawei Share OneHop NFC tags
Arduino controller for the Neato XV-11 robot vacuum LiDAR
Reverse-engineered BLE control of a smart toy
Reverse-engineer BLE toy protocols and control them from AI agents
ESPHome component for APC UPS units over the undocumented APC smart serial protocol
ESP32 firmware controlling shock collars via reverse engineered sub-GHz protocols
Unofficial reverse engineering of the Camsense X1 low-cost LiDAR protocol
Native macOS companion for the Anker Prime 160W and 250W chargers
Reverse engineered reimplementation of the CSR USB-SPI converter on a Stellaris Launchpad
Monitors and controls the Creality Pi Space filament dryer using an ESP32 on its internal bus
Documentation of the CAN protocol of Huawei R48xx 48V rectifier power supplies
Reverse-engineered Beetel M59 phone turned into a music player
ESPHome component for DeWalt Wireless Tool Control using a CC1101
USB printing to Panasonic KX typewriters and word processors by emulating their interface
Notes and utilities for reverse engineering Agilent PCIe protocol analyzers
Analysis of Hanover Displays flip-dot display firmware
Documentation of VEX Robotics internal firmware and APIs
Repurposes an ECOVACS GOAT RTK base station (ComNav K803) into a Bluetooth GNSS rover
Web Bluetooth control of the discontinued TrackR Pixel tracker from its reverse-engineered BLE protocol
Klipper integration and firmware research for the BIQU Panda Breath chamber heater via its OEM Wi-Fi protocol
Unofficial clean-room C++ implementation of the Livox Mid-360 LiDAR UDP protocol
Live control of AnyTone AT-778UV / Retevis RT95 radios over the mic bus
Tool to access phonebook, calendar and files on CDMA phones via reverse-engineered protocols
Tools and library to talk to Nokia and other mobile phones via reverse-engineered protocols
Unofficial client to retrieve location data from Invoxia GPS trackers
File manager and seem editor for Motorola P2K phones
Reimplementation of Argon 40 software for their Raspberry Pi based NAS cases