This simple LED clock module uses a highly stable DS3231 real-time clock for timekeeping. The RTC and alarm are control by the STM8S103F3 microcontroller. This module also provides a slot to install a small CR1220 type battery to back up the time and alarm configuration.
The module can power up using 5V or 3V DC power source. The necessary power source can select using a jumper in the module.
This clock module is designed to handle a generally available 14.2mm (0.56 inch) 4-digit seven-segment displays. This module use 12-pin (6-pin × 2) socket to connect the seven-segment display to the PCB, and it allows to mount the display unit off from the PCB.
The "alarm terminal" of this module is available as an open-collector output, and it allows the user to connect an external circuitry to this module.
This is a certified open-source hardware project. All the design files, documentation, and firmware source code are available to download at the project source repository. Content of this project is distributed under the terms of the following license:
- Hardware License: CERN-OHL-W
- Software License: GNU GPL 3.0
- Documentation License: CC BY 4.0