The clock is based around ESP8266-01 module and 2 - 74hc595 serial to parallel shift registers as the core for the clock. 4 transistors provide sing current and driver for each display and resistors on each segment provide current limiting.
Original revision, all power regulation of 3.3v is
applied to entire circuit. Revision 1.02 takes adventage of 2 regulators
5.0v for logic and driving display and 3.3v for the ESP SoC module. The board
can be powered through wired connection or USB mini B or ether USB mini B or USB
B connector
A plug in board through 2 inline headers provide connection into display board.
A smaller board with 0.36" displays with LEDs for colon and 2 additional user
LEDs provide visual display. push button switch can be utilized for user
function connected to Rx pin on the ESP unfortunately LDR can not be utilized as
3 signals from the ESP01 are used to drive the 74hc595 and 4th pin is connected
to the push button. Initial release of the 0.36 board has only single LED for
colon, Revision 1.01 adds additional colon LED and the 2 are separated by
resistors.
0.56" version of the display is only 0.2" taller but still the same width which
will fit into the same case but will need different front frame
Versions of the boards are available on our
Tindie store
Documents
Schematic (display & controller
board)
PCB laybout on EasyEDA
3D main case (stl)
3D face case (stl)
Sample clock code