Step-by-step project builds, maker guides, and DIY electronics instructions
Industrial sensors often speak 4-20mA. Implementing a transmitter with a 12-bit DAC and a voltage-to-current converter op-amp stage is a beginner circuit with subtle loading behaviour.
Capacitive touch with the FT6236 controller over I2C is well-supported but the calibration matrix and interrupt debounce require careful implementation for a smooth UI.
MCP23017 gives you 16 I/O lines over I2C. TCA9555 adds interrupt-on-change. PCA9685 is a PWM controller, not a GPIO expander — but it gets recommended as one. A clarification.
The STM32 internal RTC drifts around 20 ppm. The DS3231's TCXO brings that to ±2 ppm. When that difference matters and how to implement battery-backed timekeeping.