This digital dice project is an interesting project that will display in random the number from 1 to 9 on the 7 segment display. This is an alternative device that can be used to replace the traditional dice when you are playing games such as snake ladder and monopoly.
The generation of clock is done by using a 555 timer which is connected in the astable mode at a frequency of approximately 50 Hz. The 555 timer is the most commonly used integrated circuit in many projects and it is a good idea to get used to this device as soon as you can. On top of that, the cost of this IC is reasonably cheap compared to other ICs.
This clock signal is fed into the decade counter which outputs are connected to 4 bit binary adder which provides a binary output equivalent to binary input + 1. The outputs are then connected to a BCD to 7 Segment Decoder which is used to drive a common anode 7 segment display.
As shown in the schematic above, when push button PB is pressed, a square output will be generated from the 555 timer which gives a frequency of approximately 50 Hz to the 7490 decade counter IC. The frequency of the astable 555 timer is calculated by using the standard formula of the timer.
f = 1.44/[(1K + 2*1K)(0.01uF)] = 48 Hz.
The output from the 555 timer is then connected to the input of U1 7490 decade counter. When the decade counter reach the count of 9, the outputs of QA and QD will go to logic "1" and the counter is reset. The 7447 BCD to 7 segment decoder is used to drive the 7 segment common anode display.