Circuit Design

How the circuit should work:

Our circuit does not work. However, in theory, it should. With proper voltages, the lights will light up corresponding to how many switches, or sensors, emit a high voltage. For example, if the sensors do not detect any symptoms, then it will emit a low voltage. The electricity will then flow to the flip flop, and by the 555 timer, the output will lead into the logic board through the Q and Q bar in the flip flop. The Q bar output will change the low voltage into a high voltage, and since the green light is connected to a 3-input AND gate which is connected to the Q bar output, this high voltage will go through the gate and light up the green light, thus informing the user that he or she does not have any signs of the Coronavirus. Similarly, this system will work with any input given by the switches and the lights will light up in correspondence to the amount of switches emitting a high or low voltage. The switches and the voltages will run through the flip flop, the 555 timer, and to the corresponding light. The logic portion of the other instances are explained through the Truth Tables and Logic Equation sheet for this circuit.

When we tested our circuit, we found out that there is only voltages going out of the Q bar output of the flip flop. There were no voltages going out of the Q output, but there were minute voltages going out of the CLK output into the alarm circuit. Since only Q bar had voltages, this caused the green light to illuminate because we set up the logic board so that the green light will light when (C' x O' x T') = 1, which in this case is true because of the Q bar voltages making each negation true. Through this, we at least found out that our logic board is working, and we further tested it by directly inputting the voltages straight to the logic board. When we further tested the logic board by using digital primitives, when the yellow light lit up the green light lit up as well. We looked into why that happened and saw that even when a wire is not connected to any power source, there was still voltages running through the wire. We found that this was weird and a possible bug in the program, or some miscalculation on our part. With further inspection, we concluded that it was the latter.

Link to our circuit: