1. Logic Circuit Teaching Board Team 3 David Lee, Younas Abdul Salam, Andrzej Borzecki ECE 445 Senior Design TA: Ankit Jain Date: April 27, 2015

2. Purpose and Objective Promote STEM for students in grammar school Introduce students to gate level logic design Provide a simple user interface for learning Assist educators in explaining logic design

3. How It Works

4. How It Works (Continued)

5. Initial Board Layout

6. Initial Board Dimensions Top View Side View

7. Final Board Specifications Powered Logic Inputs – 3 Rows and 5 Columns Board Size – Initial Size (Length 44cm, Width 30cm, Height 16cm) – Final Dimensions (Length 60cm, Width 100cm, Height 16cm) Board Material – PVC(Polyvinyl Chloride) Logic Input Polarity with Banana Plugs

8. Board Functions Compare truth table inputs to the logic design circuit Identify errors in the logic circuit using LEDs Optimize the number of each logic gate required for the truth table Open source design with USB connection

9. Board Circuit Design

10. Testing Procedures Voltage output on the board with all components powered to ensure 5Vdc +/-0.5V Open and close power supply switch and test voltage and current output for safety Test strength of banana plug connections Test maximum current with the maximum amount of inputs connected

11. Actual Design

12. Microcontroller

13. Purpose Implement different functions that assist teaching and learning Examples include logic tester, number of gates calculator Assist with debugging any problems with the board, without having to open the board

14. Connections Structure

15. Power Circuit Microcontroller needs >6V power. DC-DC voltage booster used, voltage ~6.2 V. Higher capacitance, more voltage. 4.7uF = ~5.7V. 22uF = ~6.2V

16. NOT gate LED buffers Booster utilizes capacitors Higher current drain, lower voltage Buffer LEDs for indirect power

17. Start and Inputs Switch Floating voltage issue Solved using NOT gates Floating outputs LOW. Ground outputs HIGH.

18. Logic for Truth Table Switches Microcontroller cycles through selection logic, picks up individual values through a MUX. Same logic sent to logic board for gate values, and computation LED logic to turn on specific LEDs. Saves microcontroller ports

19. Microcontroller Code Code to test correctness of designed circuit. Accounts for number of inputs Guides student to which values are causing issues Communicates with hardware to implement functions

20. Microcontroller Code Green LED indicates correct logic Red LED indicates error, and computation LEDs point to error values

21. Additional Features Hardware debug

22. Additional Features Number of Gates Code for this feature reads truth table and compares it to a database

23. Logic Design Pieces

24. Initial Design

25. Circuit Schematic

26. 2D Schematics NOT GATE Initial sketches Preparation for 3D printing Visual sizing representation

27. 2D Schematic AND GATEOR GATE

28. 3D Renderings

29. Modifications

30. 3D Printed Logic Pieces

31. Logic Unit Assembly

32. Testing Procedures Continued AND GATE A BC 0 0 0 10 0 1 01 OR GATE A BC 0 0 0 11 1 1 1 NOT GATE AC 01 10 Voltage output for logic pieces: Logic Low 0- 0.8V Logic High 2-5.6V Plug in inputs as represented by truth tables and test the output Plug the pieces to the board and ensure stability

33. Output Testing in Volts

34. Conclusion Board performed and satisfied all requirements and verifications for the different components Voltage and current values are within range and correctly propagate logic forward Microcontroller performs checks correctly and does not interfere with design process unless logic check requested

35. Future Development Larger variety of gates for more complex implementation Additional control features, such as password protected logic verification and “test mode” Integrated timers and buzzers for logic design competitions

36. IEEE Code of Ethics To accept responsibility in making decisions consistent with the safety, health, and welfare of the public, and to disclose promptly factors that might endanger the public or the environment; To be honest and realistic in stating claims or estimates based on available data; To improve the understanding of technology; its appropriate application, and potential consequences;

37. Special Thanks To Professor Carney Professor Oelze Ankit Jain (TA) Greggory Bennett (ECE Machine Shop) David Switzer (ECE Machine Shop)

38. Questions?

39. Thank You!