Steven Engel: Engineering Portfolio
Digital Electronics
2018-2019, Mr. Milcic and Mr. Malachi
Course Description:
“This course provides a foundation for students who are interested in electrical engineering, electronics, or circuit design. Students study topics such as combinational and sequential logic and are exposed to circuit design tools used in industry, including logic gates, integrated circuits, and programmable logic devices.”
https://www.pltw.org/our-programs/pltw-engineering-curriculum#curriculum-7
In Digital Electronics, we explored various topics and completed several projects related to electrical and computer engineering. Through gaining experience on the projects, I found that I had a natural talent for working with computers and circuits. It is worth noting that halfway through the year, the class became largely self-taught; it was during this time that I thrived and knew that I would pursue computer engineering.
Table of Contents
Majority Vote Project
The first project was the Majority Vote Project. It involved producing a voting system whereby four members of a board (President, Vice President, Secretary, and Treasurer) could vote by turning switches on or off. If three or more members voted for any given measure, it would pass; however, if the President voted with only one other member, it would also pass.
Majority Vote Project Design/Development
Many skills were learned during the course of this project, such as:
AOI logic
Truth tables
Boolean Expression creation
Boolean Algebra/simplification
Circuit Design (by hand and with software)
Click on the slideshow below to view the design and development of this project.
 Truth TableFirst, a truth table was produced to test for all possible results and determine the circuit's output. From this, a lengthy, unsimplified logic expression was derived. |  Unsimplified CircuitA drawing of the unsimplified circuit was created by hand and then with Multisim, a circuit design software (shown). This design functioned correctly, but was far too complicated. |  Boolean AlgebraAt this time, boolean algebra was used to simplify the initial logic expression from the truth table. |
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 Final CircuitUsing the simplified logic expression, a new circuit was designed on MultiSim. Notice how this circuit is much simpler, with only 6 logic gates being used, compared to the original 35. This would bring costs down for a manufacturer, as well. |
Majority Vote Project: Prototype
A working prototype of the Majority Vote system was created using a breadboard. 74LS08 and 74LS32 logic gates (“AND” and “OR”) were used. The votes of each board member were simulated using switches and color-coded wires. Click on the video to the right to see the prototype in action.
Date of Birth Project
The second project in DE was the Date of Birth project. The primary objective was to continue practicing the use of AOI logic, general circuit design, and the use of the seven segment display by displaying the digits of a birthday one by one, using switches. During this time, common cathode and common anode displays were learned (see background).
Date of Birth Project Design/Development
Click on the slideshow below to view the design and development of this project.
 Truth TableA truth table was produced with 3 input switches (“X”, “Y”, “Z”) and 1 output for each displayed character. Since the birthday was in format MM-DD-YY, 8 characters were needed. Each of the characters was made of 7 segments in the display, also listed in the truth table (A-G). |  Karnaugh MapsFor each segment A-G, a Karnaugh map (alternate way of simplifying an expression), or K-map, was constructed. |  MultiSim CircuitFrom the K-maps, simplified expressions were found for each segment A-G. From these, a circuit was drawn, and then produced on MultiSim (shown). |
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 Prototype CircuitA working prototype was produced by breadboarding. Care was taken to ground and power each chip and color code the beginning inputs. |  PLD CircuitThe Date of Birth Project was recreated in Multisim and used to send instructions to a PLD, or programmable logic device. This is the circuit, redesigned to be compatible with a PLD. |
Date of Birth Project: PLD Prototype
The Date of Birth Project was recreated in Multisim and used to send instructions to a PLD, or programmable logic device. Click on the video at right to view the working circuit.
Deli Counter Project
The objective of the Deli Counter Project was to have a PLD control two seven segment displays which would count up from 0 to 80, using SSI (small-scale integration) for one digit and MSI (medium-scale integration) for the other digit. In addition, the circuit could be reset at any time with the press of a button. During this time, programmable logic, flip-flops, and MSI were learned.
Deli Counter Project Design/Development
To create the Deli Counter, a circuit draft was produced. In this draft, the MSI integration was created for the ones digit. For the tens digit, the number of flip flops needed was determined (4 needed, 0-8 or 9 states). The toggle logic was connected, as well as the reset logic. Finally, the tens and ones digit were connected in a way that when the ones counted up ten, the tens digit would count up one. From this, a design was created on Multisim to test and fix any errors in the circuit.
Click on the slideshow below to view the full design and development of this project.
 Initial CircuitThe design for the deli counter was first created in simulation mode, so that any errors could be corrected easily. The circuit shown counts to 80 and can be reset with the switch in the center. |  Final PLD CircuitThe final design was created in programmable logic mode in MultiSim. The PLD board was then programmed based on these instructions. |
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Deli Counter Project: PLD Prototype
A final, working design was created and exported to the PLD board successfully, as shown to the right (click on video to view).
60 Second Counter Project
The objective of the 60 Second Counter Project was to have a PLD control two seven segment displays which would count up from 0 to 60, using SSI (small-scale integration) for one digit and MSI (medium-scale integration) for the other digit. In addition, the circuit could be reset at any time with the press of a button. This was similar to the deli counter; however, this time only synchronous (as opposed to asynchronous) logic could be used.
60 Second Counter Circuit Design
Like the Deli Counter, the 60 Second Counter was first designed with MultiSim, and tested in simulation so any errors could be corrected with relative ease. This circuit was produced; the circuit functioned correctly, counting to 60 with the ability to reset at the flip of a switch.
60 Second Counter PLD Circuit Design
After the simulation design was produced successfully, it was replicated in PLD form. The circuit functioned correctly in simulation.
60 Second Counter Project: PLD Prototype
A final, working design was created and exported to the PLD board successfully, as shown to the right (click on video to view).
State Machine Project
For the State Machine Project, the last four digits of phone numbers were displayed one by one using a state machine. First, a map of all possible states was created (1, 3, 5, 7). Then, a table was created to form K-maps, from which simplified expressions of the logic for switching states were derived. Finally, a working design was created on MultiSim, shown to the right (click on video to view).
Arduino Projects
During this unit, students learned to work with the arduino board, programming language, and related components through a series of unique projects. Click on the slideshow below to view these projects.