Intro: Date of Birth Project
The Date of Birth Project is a breadboard circuit that displays a person's day of birth (in this case 07/21/1996). Design Specifications: 1.) must be common cathode 2.) 150 ohms-270 ohms 3.) K-mapping 4.) 2 chips must be NAND 5.) 2 chips must be NOR
Step 1: Starting the Project
To begin this project you need to understand exactly what you are getting yourself into: A seven segment display is similar to a scoreboard you find at a basketball game. Each segment acts on its own depending on the word. So, this project has three switches so each switch can go off or on. Where a switch is off or on changes the number on the seven segment display. This is a quick foreshadowing of all the steps that will be forthcoming. First, you create a chart that will show a number on each line of your truth table (truth table is shown in the picture). Also, I've included all the supplies needed for this epic adventure.
Step 2: K-Mapping
After you finish your truth table, you are now ready to develop a word for each segment. To find your word, you use a method called K-mapping; K-mapping is a quick and easy process to find groups when the switch is on (creating a word). The picture has a couple examples of when a segment is on, the group is created, and the what word is implemented.
Step 3: Developing the Circuits
After you have all your words for each segment, you are ready to develop the circuits. Picking the type of circuit is simple, draw a circuit for AOI, NAND, and NOR then choose the circuit that has the least amount of chips (less chips= more space on breadboard). Repeat this step for all segments. For this birthday there are 12 chips including R-Pack, 1 inverter, 2 AND, 2 OR, 2 NAND, and 4 NOR.
Step 4: Creating the Complete Circuit on Multisim
After all circuits are drawn and planned out, off to Multisim where you will put all your circuits together and see if you did it correctly. A quick tip to minimizes clutter: use a bus line to distribute the switches instead of trailing all the way back to the start. Now, after you tested your circuit and got the correct numbers you are on your way to breadboarding.
Step 5: Planning the Process
Before you dive into a pool of wires and chips, plan out your process and prevent yourself from looking like a plate of spaghetti. A helpful strategy to keep your wires on the board is to run the switches across the board and simulate a sort of bus line. You should have a process that is easy for you to follow if you ever lose your train of thought.
Step 6: Start Breadboarding.....
This way seem a bit overwhelming but since you have some idea on how you are going to breadboard it would be smart to do one segment at a time and test it before moving on to the next segment. This will save you time if you ever have t troubleshoot or find yourself lost. Also, check to make sure you have the right chips, power and ground our set up correctly and make sure all chips are properly set up to power and ground.
Step 7: How to Demonstrate Your Finish Product
Now, that you have connected all segments to the cathode and everything is working properly you are already to show off to your friends. Look back at your truth table and go down the table moving the switches in the correct order. If your seven segment display shows you the correct numbers then you are golden ponyboy.