Desktop pen holder and calendar made with raspberry pi pico

In theory, it could connect to Google Calendar and show today's events while still being ongoing. Also on the list of features to be implemented is a switch or sensor that changes mode when the pen is removed, and buttons or touch controls for the user interface.

Schematic PCB

MiniQ: a mini quadcopter

MiniQ is a mini quadcopter that is open source from hardware design to control algorithm. The algorithm used for the Altitude Heading Reference System (AHRS) is the DCM complementary filter. The system calculates the height and controls the output PWM of the four motors 1600 times per second. It can be controlled remotely via Bluetooth (Bluetooth Serial Port Profile).

Schematic PCB

SpaceX Starlink user terminal modification

Author Lennert Wouters demonstrated how to execute arbitrary code on Starlink user terminals via a custom modchip injected with voltage faults, and notified Starlink of these vulnerabilities.
Although the details are open source, the author does not sell the finished product, nor does he provide details of the modified endpoint firmware and fault injection used in the attack.
The transformation is to use a Raspberry Pi microcontroller

Schematic PCB

Open source audio amplifier

The power supply has a stable symmetrical +/- 40 V to ensure optimal performance.
Maximum power (THD 1%) approaches 100 W into 8 Ω load and 190 W into 4 Ω load (see measurements). All parts are through-hole, making it easy to build the amplifier. The design is completely symmetrical.

Schematic PCB

Automatic doorbell with object detection

Every house has a doorbell. When a visitor arrives at a home, he looks for the doorbell switch and rings it to let us know his presence. What if a person coming to your home cannot find the doorbell, or the person is too short to reach the doorbell? The object detection circuit installation below is for reference. The circuit will automatically sense the presence of a person and ring the doorbell.

Teacher ChaN’s headphone amplifier design

Teacher ChaN’s headphone amplifier design

Schematic PCB

12f629 microcontroller decodes KEELOG source code, commonly used remote control rolling codes

Schematic PCB

51+sl811 source program + schematic diagram for reading and writing U disk

Schematic PCB

Display of cool effects of 448 digital tubes simulating water flow

Kinetic Digits is a mechanical flipping digital display, consisting of 448 7-segment digital tubes, simulating the effect of water flow. For various effects, it can be produced with the help of the provided host computer.

Schematic PCB

Make a USB-C power supply (understand the principles of USB-PD in depth, including schematics and English design instructions, etc.)

A simple power supply design based on USB-PD, USB-PD allows to provide voltage up to 20V (current up to 5A), the author shared his design details, you can have an in-depth understanding of the working principle of USB-PD.

Schematic PCB

Tah: Arduino-compatible BLE platform, which can be used as beacons, microcontrollers and HID devices (including schematics, source code, etc.)

Tah - Control anything from your smartphone, open source, Arduino-compatible Bluetooth Low Energy (BLE) platform that can be used as a beacon, microcontroller, and HID device.

Schematic PCB

Novena: an open source computer based on Freescale and Xilinx FPGA, designed for use as a desktop, laptop or standalone board

Novena is a 1.2GHz, Freescale quad-core ARM architecture computer tightly coupled with Xilinx FPGA. It is designed for users who care about free software and open source, and/or want to modify and extend their hardware: all documentation for the PCB is open and freely downloadable, the entire operating system can be built from source, and it Comes with a variety of features that facilitate rapid prototyping.

Schematic PCB

Maker LED Display: Arduino programmable and internet-connected LED matrix display

Maker LED displays make using LED matrix displays easy. The ready-to-use, fully assembled circuit board has everything you need to run your monitor - just plug it in! Using and customizing the display is easy, with a specially written Arduino library and a dozen pre-made examples. The Maker LED display also has Wi-Fi so it can connect to the Internet to retrieve and display information. Choose between 32 x 9 pixel or 64 x 9 pixel versions and select LED color: white, blue, red, green, orange or violet.

Schematic PCB

Nixie Tap: Minimalist Wi-Fi Nixie Clock

Nixie Tap is a compact and simple Nixie clock. It's powered via a micro USB connector, so you can power it from any USB port or an old phone charger. It also has Wi-Fi, so it can automatically synchronize with an NTP time server once connected to a wireless network. We made the Nixie Tap look good on our desks, and we hope it looks good on yours.

Schematic PCB

A tiny, open source USB computer for security applications

The USB armory Mk II is a full-featured computer (900 MHz ARM® processor, 512 MB RAM, Bluetooth, USB-C) in a small form factor, designed from the ground up with information security applications in mind.

Schematic PCB

Inkplate 10: Low-power, easy-to-program, open-hardware e-paper display with Wi-Fi support and 9.7-inch screen

Inkplate 10 is a powerful, energy-efficient, Wi-Fi-enabled ESP32 development board with a recyclable 9.7-inch e-paper display. It's open hardware supported by open source software libraries, and it's easy to program whether you prefer MicroPython or the Arduino IDE.

Schematic PCB

SmartLED Shield for Teensy 4: Drive high-quality graphics to your HUB75 RGB matrix panel with Teensy4

Want to add lots of LEDs to your Arduino project? HUB75 RGB panels are a great way to do this as they are much cheaper than addressable Neopixel/WS2812 LEDs (typically 10% of the cost per LED). They are also available in a range of pixel densities (from 2mm to 10mm pitch) to better suit your project needs. However, using a microcontroller to display high-quality graphics on a HUB75 panel is complicated because the panel requires precise timing and constant refreshing of pixel data. That's where Teensy 4's SmartLED Shield comes in.

Schematic PCB

ANAVI Macro Pad 2: Open Source Programmable Two-Button Mechanical Keyboard with Backlight

Every key on the ANAVI Macro Pad 2 can be reprogrammed to be used as a macro or even as a dedicated shortcut key, making it ideal for many applications in a variety of industries.

Schematic PCB

Inkplate 6PLUS: Versatile, easy-to-use, Wi-Fi enabled 6-inch e-paper display with touchscreen and front light

Inkplate 6PLUS is a powerful, energy-efficient, Wi-Fi-enabled ESP32 development board with a recyclable 6.0-inch e-paper display equipped with touch screen and headlight. It's part of the Inkplate family of open hardware powered by open source software libraries, making it the easiest electronic cardboard to use, whether you prefer the Arduino IDE or MicroPython.

Schematic PCB

Steno-Flex: An innovative, cheap, customizable shorthand

Steno-Flex is a unique, low-cost stenotype that matches standard stenotype layouts and key actions. By using flexible keys with touch sensors, Steno-Flex is able to simplify the stenotype's design and mechanics, making Steno-Flex lighter and less expensive than current stenotypes on the market. Steno-Flex uses modern materials and electronic equipment, combined with computers, to allow students and novices to develop shorthand skills. Just plug the USB cable into your computer, launch the open source shorthand software Plover, and you're ready to go. Provides online tutorials and guides. Steno-Flex is an effective device for people who want to learn shorthand and develop real-time speech transcription. Shorthand technology is evolving to become the standard solution for data entry, from simple keyboards to sophisticated shorthand controls.

Schematic PCB