This article shows how to build a simple DIY smartwatch using the NULA Mini and an SSD1306 OLED display, explains the hardware, interface logic, time and weather features, and overall project structure.

The article explains what PWM is and why it is used to simulate analog output with digital signals. It covers cycles, period, frequency, duty cycle, how to calculate duty cycle and average output voltage, and shows an Arduino example that fades an LED using analogWrite.

This article explains what UART is, how it works, what baud rate and frames are, how start, data, parity and stop bits function, and where UART is used in practice.

Overview of the MAX98357 I2S digital audio amplifier and how digital amplification works. Explains I2S signals, wiring to ESP32, speaker/audio format selection, and an ultrasonic warning project that plays WAV audio when distance stays in range.

This article explains what the SPI communication protocol is and how it works. It covers signals like MOSI, MISO, SCLK and CS, explains sending and receiving data, multiple peripheral configurations (regular and daisy-chain), and lists the main advantages, disadvantages and real-world uses of SPI.

This article explains what I2C is, how it works, how devices are addressed, why pull-up resistors are needed, and how to use and troubleshoot I2C in projects.