Most of the digital clock available in website is only capable to display hour and minute only. Now, here is a digital clock by that shows not only hour, minute and second but also alarm time. Best Engineering Projects (BEP) verify the project Digital Clock with Second and Alarm time display with the help of ten 7-segment display and clock chip mm5387ANN.
Circuit Description of Digital Clock with Seconds and Alarm Timer Display
The entire circuit of Digital Clock with Second and Alarm Display is build around clock chip IC (IC3) followed by CMOS decoder (IC1, and IC5), timer IC NE555 (IC2) and 14-stage counter IC (IC4). Timer IC NE555 is used here as multivibrator which further combined with CMOS decoder IC (IC1) to switches the two push-to-on switch for second and alarm, output from pin 2 and 3 of IC1 is connected to pin 31 and 32 respectively in order to switch second/alarm time display. The output pin 4, 3 and 2 of IC2 is connected to transistor T2 through T4 respectively in order to ground all the 7-segment display.
The upper 3-pair of display (DIS1 through DIS6) is used to display hour, minutes and second, where display 1 (DIS1) of hours used only two segment (b, c) of the LED to display 1 when the hour display reaches 10 and above. The lower four 7-segment display is used to display alarm time. As in hour display only two segment b and c of the LED is used in order to display 1 in display 7 (DIS7). The f and e segment of DIS7 are used to represent AM and PM respectively for the alarm time display.