Main features

  • Light compact 3d print design with magnets.
  • Use a single CR2032 coin cell that will last longer than a year.
  • Put image files on SD card (SD card needs to reformatted).
  • Setup files to set update frequency and more.
  • Easy to reprogram using a launchpad.
  • Code is writing in Energia, a modified version of the Arduino IDE

Current software features

  • Load Setup on startup.
  • Intervals are set in 2 minute interval. For ones a day update use 720.
  • Low Battery voltage detection.

Hardware

  • Display: 2.7 inch b/r/w epaper display. More detail  here .
  • MCU: Texas Instruments MSP430G2553IPW20R  (TSSOP-20)
  • 32.768 kHz crystal for accurate time keeping.
  • Mirco SD card socket.
  • 3.3v boosting using AAT1217-3.3. SD cards not happy with less voltages.
  • The necessary components plus 24 Position FFC, FPC Connector for the epaper display.
  • Extra reset switch and mode switch.
  • Header to flash the MSP430 and serial (UART) for debugging.

Power usage

  • Standby current average 4.3 uA . When keeping time.
  • Update power consummation  aground 100 uAh . When refresh screen with new picture.
  • Battery will easily  last over a year if update once a day.
  • Because of  the SD card power spikes, need a good quality make and will not drain to empty before read failures.