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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#rtc
5 tutorials
Arduino: real timekeeping and alarms with the DS3231 RTC
Give your Arduino a real clock with the DS3231 RTC module. Set the time, read it back, and fire alarms that survive power loss, drift, and reboot.
Arduino: build a digital clock with DS3231 + OLED
Build a desk clock that never drifts: a DS3231 RTC keeps time, a 0.96 inch SSD1306 OLED shows it big. Two I2C devices on the same two wires, plus a button to set it.
Arduino: datalogger with RTC + SD card for timestamped sensor files
Log sensor readings to an SD card with real timestamps from a DS3231 RTC. CSV files your spreadsheet opens directly, and a clock that survives power cuts.
ESP32: RTC memory, the fast persistent storage that survives deep sleep
Use RTC_DATA_ATTR to keep state across deep sleep on the ESP32. Boot counters, last-known sensor values, and the gotcha that it does not survive a power cycle.