University of Southern California The USC Andrew and Erna Viterbi School of Engineering Pre-College Summer Programs - Student Portfolios

 Step One: List out all the possibilities and create a truth table

Risk # 1  Risk # 2 Risk # 3 Result
0 0 0 Green
0 0 1 Yellow
0 1 0 Yellow
0 1 1 Red
1 0 0 Yellow
1 0 1 Red
1 1 0 Red
1 1 1 Alarm

This table is written according to the rules:

1) Lights up green LED when no risks are presented

2) Lights up yellow LED when one risk is presented

3) Lights up red LED when two risks are presented

4) Sounds alarm when all risks are presented

 Step two: Boolean Algebra Equation

If,

Risk Factor #1 presented  = A

Risk Factor #2 presented = B

Risk Factor #3 presented = C

Then,

A'B'C' = Green LED

ABC = BUZZ

A'BC + AB'C + ABC' =  Red LED

A'B'C + A'BC' + AB'C' =Yellow LED

Step three: Design a logic circuit and stimulate it on Yenka

 

 Step four: Arrange a pin diagram

 Step five: Build the device

Day one: Finished the individual circuits of the green LED, red LED and the buzzer. 

 

Day two: Connecting all the circuits with the 555 timer, and the flip flop. 

 

 References

https://www.youtube.com/watch?v=oQrrxiFLoBQ- 555 Tutorial

https://www.youtube.com/watch?v=nwIEgd8uAIs- D Flip Flop Tutorial

https://www.youtube.com/watch?v=vAfwte8-7d4- Capictors in Series and Parallel