Basic Digital Logic Gates Emulator: A Learning Tool for Kids and Adults

Creators:

· Benjamin Miller

· Mason Marshall

Faculty Advisor: Dr. Rohit Dua

System Description:

The goal of this project was to find a fun and innovative way to teach children about digital logic gates. An interactive system was designed, built and demonstrated that allows the user to understand the functioning of basic 2-input logic gates.

System Block Diagram

The interactive system comprises of the facility to select, by the teacher, the 2-input gate under study and the method to excite the logic gate input. It was desired to make the learning tool fun with an innovative method, to change the gate input logic level, which would mimic a “magic show”. This feature was implemented using two beams of light falling on their respective photoresistors. Letting the light fall on the photoresistors, along with associated electronic circuitry (Circuit Diagram: ), allows logic 0 (low voltage level) as the input into the gate. Blocking the light, with the hand, allows logic 1 (high voltage level) as the input into the gate. Children enter logic 1 by using their hands to block the beam of light from hitting the photoresistor. The logic levels are transmitted to the logic gate, which is housed in an Altera® DE II FPGA board. The multifunctional 2-input gate was created using Quartus® II software (Circuit Diagram:). The teacher can select the logic gate, under study, using switches on the Altera® board. The logic gate could be switched between AND, OR, XOR, NAND, NOR, and XNOR gates. The output of the device is connected to an LED matrix, which lights up when logic gate output is high.

Overall System

Sample Videos: Click on a picture to view the YouTube video

System Overview Demo 1

Demo 2 Demo 3

Demo 4

Demonstration Venue:

· Missouri Society of Professional Engineers (MSPE) sponsored Discover Engineering Day held on February 22, 2014, at the Cooperative Engineering program, Missouri State University (MSU), Springfield, MO

Observational Conclusions:

· The interactive system was found to be fun to use and had a certain “wow” and “cool” factor to it.

· Children found the tool easy to use. They could test each input condition, for a particular logic gate, multiple times to allow the information to “sink in”.

· The interactive learning session helped increase the children’s curiosity about a digital system. They were eager to learn more about the subject matter. When told that all modern-day electronic products, including cell phones and video game hardware, for example, were made from basic logic gates, they were excited about learning more.

· Older children were able to retain more information than younger kids. They were able to predict the behavior of complimentary gates better than younger kids.

· The younger kids found the tool to be fun to use. They needed help with predicting the behavior of the complimentary gates. It is anticipated that their knowledge would increase if they spent more time practicing with the system.

· Adults also found the tool to be very informative and interesting.

Future Work:

· While the system is fully functional, the teaching delivery and student’s information retention testing methodology needs to be improved. Future work will concentrate on developing better assessment methods to see whether a student has actually learnt the working of logic gates.

· Designing a better system. It is anticipated that hand held units, resembling toys, can help improve a child’s understanding of the working of the logic gates if it can be made into a puzzle form. Efforts will focus on the development of such systems.

Acknowledgements: The design group is grateful to Dr. Douglas Carroll, Director of the Cooperative Engineering program, for providing the required components to build the system.

The Design Team: Mason Marshall (left), Benjamin Miller (right), Dr. Rohit Dua (far right)

Missouri University of Science and Technology/Missouri State University, Cooperative Electrical Engineering Program, Springfield, MO