Date of birth
We were challenged with the task of designing a circuit that would display our date of birth on a single common cathode seven-segment display. We had to include a current limiting resistor (150-270ohms), make at least one segment using NAND only or NOR only logic, and use Karnaugh mapping to obtain the simplified logic expression for each of the seven segments. You know, all of the basic fun stuff.
truth table
This truth table shows which inputs and outputs will result in the number wanted on the display (your date of birth). X, Y, and Z are the binary inputs and a-g on the chart represent the seven segments for the seven segment display. In order for a certain form to be shown the seven segments need to be powered in different areas which is what the ones and zeroes under the letters show. Under D is the number that will be shown on the display. An X is a "don't care" value which means that we can make it what we want.
k-mapping
date of birth circuit
date of birth bill of materials
Breadboarding
I didn't encounter many problems in breadboarding because I am becoming a wizard in this, but it was still semi-difficult to really construct the circuit from a drawing or multisim picture. It was also the first time that I got to use this type of breadboard with the display on it. Color coding the wires was a bit tedious to do but adds some sort of order and form to the breadboard.
conclusion
During this project I learned how to get the seven segment display to display certain numbers. I learned how to I also got to use a different type of breadboard than before, so that was pretty cool. The only thing that I would change when I do this again is probably just do it faster. For this project, we had to use K-mapping instead of the previously learned Boolean algebra. K-mapping is way faster and more efficient than Boolean algebra. It is easier to make mistakes using Boolean algebra because you have to see and apply the different laws and theorems (Boolean, Consensus, DeMorgan's, Commutative, etc.) in order to simplify the logic expression. K-mapping is simpler because you're taking the outputs directly from the truth table and using them to get the simplest form of the logic expression. I like this project because it shows you how digital displays come to be like on scoreboards, digital signs, etc.