SEVEN SEGMENT CLOCK

in this tutorial, I am showing how to build a seven-segment display clock

Things needed

1. 4* common anode seven segment displays https://amzn.to/3aDfwtP
2. Arduino UNOhttps://amzn.to/2VXJOlO
3. 3 push buttons https://amzn.to/2KxexB8
4. Ds1307 rtc module https://amzn.to/2zmkG0p
5. Common PCB https://amzn.to/3cPaNXP
6. 2*leds https://amzn.to/2VSgkWB

As the name indicates seven segment displays has 7 segments. each segment is a single led and all the 7 LEDs connected together with a common pin that may be a common positive or a common negative and arranged in a specific style.

A typical 7 segment display has 10 pins  arranged in top and bottom each of middle pins are common pins 

 And others are to control  corresponding seven segments

 Circuit diagram

we have 4 displays that is totals of 4*8=32 pins to control this our Arduino doesn't have 32 pins so how to do this. yes, multiplexing...

so we connect all segments together that is segment A of 4 displays together, segment B of all displays together and soo on ...

now we have 7 common segment pins and 4 common anode pins that is total 11 pins

 yes our Arduino has 11  pins .by using multiplexing lets control 4 displays with 11 pins instead of 32

connections

 I connected everything according to the circuit

 connect  one end of  3 push buttons together  and connect  to A0, A1, A2

RTCmodule works on i2c communication so connect 

SDA TO A4 

SCL TO A5

GND TO GND

VCC TO 5V

REPLACING THE ARDUINO UNO WITH HOMEMADE ARDUINO

to save some space I replaced Arduino with my diy Arduino

download code from here