Binary clock with RTC ds323 for arduino
First install the DS3231 library. If you use a different version than I have, then just replace the mn and hr functions with the equivalent library calls from the one you are using to get the current hour and minutes in decimal (DEC) format.
Connect 10 led pins to Arduino digital 4-13. Pins 4, 5, 7, 8, 12, 13 are minute pins, pins 6, 9, 10, 11 are hour pins. Connect so that four leds on one end are assigned to the PWM pins 6, 9, 10 and 11.
Connect the power and ground on the RTC module.
Connect SDA on the RTC to SDA on the Arduino (Uno A4)
Connect SCL on the RTC to SCL on the Arduino (Uno A5)
Set the time on the RTC module (currently not implemented)
After those steps, the leds should light up, representing in binary the current time in HHHH:MMMMM format. For example, 11.22am is 0111:010110 (with 1 representing a lit led).