Built and tested circuits that you can incorporate into your custom PCB projects.
Most of these circuits are also part of my listed projects.
SL2.1a USB hub
Cheap, available and hand-solderable IC.
CB1 Microcontroller board
Full project example using RP2040, external ADCs and port expanders over I2C, and much more.
Full project example
Embedded ATMEGA32U4, USB hub, matrix wired buttons, encodes and funky switches ++.
Voltage divider circuit to reduce the pin requirements of a 12-position switch to a single analog pin.
WS2812 LED strip
An example of chained WS2812 RGB LEDs
3.3 V regulator / FE1.1s hub / ADC
Collection of useful circuits, including 4-channel external 16-bit ADC and FE1.1s USB hub with port activity indicators.
Melexis hall sensor with noise filtering
A hall sensor circuit with an RC-filter.