Hardware: M5Paper, stable power source. 2. Strategy: The ESP32-D0WDQ6-V3 offers deep sleep modes. Use esp_sleep_enable_timer_wakeup() for periodic wake-ups. 3. Wiring/Logic: Disable unnecessary peripherals (Wi-Fi, BT) before sleep. Save critical state in RTC Slow Memory (4KB accessible during deep sleep). 4. Commands: Before esp_deep_sleep_start(), configure external wake-up GPIO if needed. For Wi-Fi wake-up, use esp_wifi_set_ps(WIFI_PS_MIN_MODEM) in light sleep, or manage reconnections after deep sleep. 5. Verification: Use a multimeter in series to measure sleep current (target <10µA). Check for RAM data loss. 6. Deep Dive: Implement an adaptive algorithm that adjusts wake-up frequency based on Wi-Fi signal quality detected in the previous cycle.