Simple, high-quality condenser microphone DIY for under $100

Schematic PCB

A low-profile version of full-featured software radio based on Raspberry Pi Pico (fully open source + detailed explanation)

With just a Raspberry Pi Pico, an analog switch and an op amp, you can build a powerful SDR receiver covering the LW, MW and SW bands. Capable of receiving signals from halfway around the world.

Schematic PCB

Flipper Zero: an open source geek multi-function tool based on STM32W55B

Flipper Zero is a portable multi-tool designed for developers and geeks with a toy-like body. It enjoys exploring digital content such as radio protocols, access control systems, hardware, and more. It's completely open source and customizable, so you can extend it in any way you like.

Schematic PCB

Smarthome-dashbutton: smart home control button

This is what smart home enthusiasts want to control their entire lights, thermostat, or any other smart device from their couch without having to activate a wall switch.

Schematic PCB

Zhihuijun's new work: Hanwen smart keyboard with FOC force feedback knob, multi-function, modular mechanical keyboard (schematic, firmware, etc.)

The keyboard uses a modular design. The multi-functional scene interaction module on the left can be replaced with various custom components. By default, a Dynamic component with an e-ink screen and FOC force feedback knob is used; the keyboard body uses a shift register method to implement the key scanning circuit; The module and keyboard body can be used alone, or they can communicate and call each other through the serial port protocol.

Schematic PCB

200 W Game Console AC-DC Adapter GreenPoint® Reference Design

short-term weather forecast system

The author is located in an area with a lot of convective weather and hot and humid weather. I stared at it silently, and saw that the clothes to be dried came in and out five or six times a day... Weather forecast on the mobile app? Weather warning text message? It can only be regarded as a late report. I am lazy, do it myself, have enough food and clothing...

Schematic PCB

NXH3670ADK development kit

NXH3670ADK development kit

Open Source Electromyography EMG Project

In the open source electromyography project shared here, the author used this product to create a computer game control effect.

Schematic PCB

FRDM-KW36: Freedom Development Kit for Kinetis ^{® KW36/35 MCUs}

FRDM-KW36 is a development kit for the KW35/36 MCU that provides connectivity for Bluetooth Low Energy (BLE) v5. KW36 integrates CAN/CAN-FD connection.

Schematic PCB

QN9090DK: Development platform for QN9090/30(T) wireless MCU

Highly Scalable QN Wireless MCU Application Development Platform This development kit is enabled by the QN9090T which supports Bluetooth 5 and NFC.

Schematic PCB

255 W, 80PLUS® Silver Certified ATX Power Supply GreenPoint® Reference Design

IoT gateway solution

Based on the modular IoT framework, NXP provides an IoT use case-specific integrated development experience (IDEx) suite to accelerate IoT system development with pre-integrated, comprehensive and fully documented out-of-the-box IoT system solutions.

Plant Bot: an open source project for caring for potted plants based on ESP32

Plant Bot is an open source project based on ESP32 that allows a single PCB to perform the functions of detecting humidity, watering, providing lighting, and controlling and communicating with the user via WiFi/BLE.

Schematic PCB

NxH3670 SDK board

This user manual describes the different user configurations of the NxH3670 SDK board.

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

60 W USB-PD and Quick Charge 3.0 Buck-Boost Reference Design Documentation Package

PNEV512R: EXPLORE-NFC - Exclusively supplied by element14

EXPLORE-NFC - exclusively supplied by element14

syzygy-epc901: SYZYGY and EPC901 CCD + 50MSps ADC

The EPC901 is a 1024x1 CCD sensor capable of providing 50MHz pixel output. It outputs analog voltage from the CCD element. The author paired it with a 50MSps ADC on a SYZYGY board. The datasheet says it can run up to 50k fps. External I/O is provided via optocouplers to facilitate connection to external trigger sources such as motion controllers. This board will assist in conducting experiments on the new PnP platform. Objects can be moved through the line scanner to capture the position of the photo.​

Schematic PCB

Electronic door guarding (knock detection, reminder)

The acceleration sensing unit (RSL10+KX023) attached to the back of the door is used to detect vibration and movement to detect events such as opening the door and knocking on the door. It also interacts with the terminal through information through BLE and can view the log on the handheld terminal. Handheld terminals are also implemented with RSL10. After powering on, it automatically scans the target device and connects to it. After connecting, it obtains the time and date information of the device (which can be modified at this time), and then enters the log interface. The wireless sensing unit and the BLE terminal exchange information through the BLE connection.

Schematic PCB