Overview This is the latest, and probably final iteration of my ESPCLOCK project. You can find ESPCLOCK1 here , and ESPCLOCK2 here . The main differences between ESPCLOCK3 and ESPCLOCK2 are: Use barebones ESP-07 instead of WeMOS D1 Mini to reduce deep sleep power draw. Use PCF8563 RTC to clock the ATtiny85. PCF8563 is chosen over the more popular DS3231 RTC due its vastly lower power consumption. Using a RTC to clock the ATtiny85 allow us to use the POWER_DOWN instead of IDLE sleep mode, which minimizes power draw. As a result, the ATtiny85 code is also vastly simplified because we don't have to play with Timer1 to get an accurate 1Hz signal. Use diode clamp to limit the voltage pulsing the analog clock. Connecting to the analog clock directly using the ATtiny85 pins running at ~3V requires the clock pulse to be longer (~200ms) and increases power draw (due to reduced MCU sleep time). In addition, the higher voltage causes ticks to miss occasionally. The diode cl
I quick-formatted an old 2GB SD card using Windows and popped it into the Ender 3, but it was not recognized. I also tried a full format based on what others have mentioned on Reddit, but that didn't work as well. Finally, what worked was quick-formatting the SD card using the SD Memory Card Formatter by the SD Association.