Pico: log sensor data to microSD with timestamps
Wire a microSD card to a Pico over SPI and write timestamped CSV sensor logs that survive power loss. The offline data logger pattern.
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#spi
7 tutorials
ESP32: read RFID tags with the RC522
Wire the $3 MFRC522 RFID reader to an ESP32 over SPI and build the tap-to-unlock pattern: card UID list, relay output, event logging.
ESP32: add 8 analog inputs over SPI with the MCP3008
The ESP32 loses half its ADC pins the moment Wi-Fi turns on. Add 8 clean analog inputs with a $4 MCP3008 over SPI: wiring, real pins, and a full 8-channel sketch.
ESP32: draw graphics and text on a color TFT (ST7735/ST7789)
Wire an ST7735 or ST7789 color TFT to an ESP32, draw text and shapes, update a live readout without flicker, and fix the classic black-screen and wrong-color problems.
ESP32: debug with a logic analyzer and protocol decoders
When the Serial.print tells you nothing, the I2C bus tells you everything. Pick a $10 clone or a $400 Saleae, install Sigrok and PulseView, decode I2C/SPI/UART.
ESP32: drive a MAX7219 8-digit 7-segment display
Wire a MAX7219 to an ESP32 to drive an 8-digit 7-segment display over SPI. The right pick for showing sensor numbers, counters, or clocks.
ESP32: drive a 74HC595 shift register for 8 extra output pins
Add 8 output pins to your ESP32 using only 3 GPIO pins and a 74HC595 shift register. For LEDs, relay arrays, and 7-segment without a driver.