Agilent E3631A DC power supply schematic diagram

Several 51 chips were also used in the design.

Schematic PCB

Hardware circuit realizes SPI to Ethernet 10BASE-T

It introduces in detail how to build an SPI to 10BASE-T to realize network data sending and receiving. 10BASE-T uses two differential pairs: one for transmission and one for reception. Each pair is coupled through a transformer and the signals are differential and Manchester encoded. All schematics and diagrams are open.

Schematic PCB

Homemade flexible capacitive sensor

By CNC engraving a PCB in the following manner, the curved pad can perform capacitive sensing in 3 different directions and ultimately detect the 3D position of the finger.

Schematic PCB

Open source handheld vector network analyzer NanoVNA

NanoVNA is a small handheld vector network analyzer with LCD display and battery-powered portable device. This project aims to provide a useful RF gadget.
The measurement frequency range is 50KHz - 300MHz, and there are many derivatives based on this design on the Internet.

Schematic PCB

Rodeostat: Potentiometer for electrochemistry, fully open source

It's all open source, and their documentation is very detailed, which is a rare learning material.

Schematic PCB

High resolution magnetic rotary encoder based on RP2040

This is a mature development board combined with a magnetic rotary encoder, which uses a Raspberry Pi RP2040 microcontroller with a base resolution of 36, expandable to 36,000 steps per revolution.

Schematic PCB

Use waste water bottles to produce 3D printer filament recycling machine

3D printer filament can be produced from discarded water bottles, which will serve two key purposes: recycling plastic waste and producing 3D printer filament at extremely low cost.

The authors hope that as many people as possible will replicate and improve on this project. Therefore, all CAD, firmware and other resources are open source. Special consideration was also given to ensuring that all parts and tools used in the build process were easily sourced.

Schematic PCB

3D printed portable wind turbine

The wind turbine is mainly 3D printed and equipped with a BLDC motor as a generator. Foldable and no larger than 2L soda bottle. Easy to replicate and low cost to manufacture.

Schematic PCB

STR-NCS32100-GEVK: Reference design for ON Semiconductor rotary position sensor NCS32100

Schematic PCB

Starfish: an open source project for motor control board using component pick-and-place of RP2040 and TMC2209

Starfish is a pick and place machine control board built on the Raspberry Pi RP2040 microcontroller and Trinamic TMC2209 motor driver. This control board has some similarities to a 3D printer control board, but it has some unique issues to solve—including controlling solenoids and communicating with vacuum sensors. All board information is open source, and detailed explanations are provided to help you copy successfully.

Schematic PCB

Reference design of Epson multimeter microcontroller S1C17M02/M03

Can measure DC/AC voltage, DC/AC current, resistance, inductance, capacitance, diode, frequency. Built-in 16bit ADC, digital filter, RMS effective value circuit and peak hold circuit. Multimeter control unit integrated with microcontroller, officially launched reference design kit, powered by button battery, including schematic diagram.

Schematic PCB

Raspberry Pi microcontroller 100Msps dual-channel oscilloscope software and hardware are fully open source, including detailed instructions

The current design solution uses an 8-bit ADC chip ADC08100 and a 100M bandwidth front-end analog circuit. In fact, if you want to play, you can improve the indicators and use AD9288 or the domestic alternative MXT2088. One chip has two channels and achieves a 250M sampling rate through rapid alternating sampling.

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

Avem: A lightweight UAV flight control based on STM32F103

A lightweight UAV flight control based on STM32F103.

Schematic PCB

TI releases space-grade 3-7V input, 24A/0.95V output reference design

This is a 24-A DC/DC space-grade power supply hardware reference design.
With the advancement of FPGA and ASIC technology, the core voltage requirements are getting lower and lower, but the current requirements are getting larger and larger. The latest space-grade FPGAs and ASICs require low voltage and high current to meet their core power consumption.

Schematic PCB

ReflowMaster: open source reflow master control based on the magic oven (schematic, PCB, gerber, source code, etc.)

Reflow Master Pro is designed to work in any oven - no algorithm adjustments required! That said, if you really want to tweak, you can switch from the classic Reflow Master algorithm to PID control and adjust your settings to your liking.

Schematic PCB

E-books based on Raspberry Pi microcontroller

This time it’s an e-book based on the Raspberry Pi.

Schematic PCB

Low-cost 2.5KV USB power isolation solution (schematic + BOM + gerber, etc.)

This is a low-cost isolation achieved through a power transformer. Since the transformer is more convenient for AC isolation, but DC is not suitable, ATtiny412 is specially used for control.

Schematic PCB

OPen Book: a fully open source e-book that supports all languages ​​and breaks down working principles (schematics, PCB, source code, etc.)

Open Book is an open hardware device for reading books in all languages ​​of the world. It includes a large screen and navigation buttons, as well as audio options for accessibility and ports to expand its functionality. Its fine screen printing aims to demystify Open Book's own design, breaking down for curious readers how the book works and how they can create one for themselves.

Schematic PCB

VESC – Benjamin’s open source brushless motor driver (schematic, PCB, firmware, tool software, etc.)

ESC is the abbreviation of Electric Speed ​​Controller, that is, electronic speed controller, or ESC for short. The author is Benjamin Vedder, so it is called VESC. You may have heard of it, which is Benjamin ESC. This project is mainly divided into several parts, VESC firmware, bill of materials, VESC hardware, and VESC tool software. It is a very complete software and hardware project, and the supporting software is also excellent.

Schematic PCB