Biomedical Engineering

Biomedical engineering is a multidisciplinary field that applies principles and problem-solving techniques from engineering, biology, and medicine to improve human health and healthcare. It involves the design, development, and maintenance of medical devices, equipment, and software used for medical purposes.

Electrical Engineering

Electrical engineering is a branch of engineering that deals with the study and application of electricity, electronics, and electromagnetism. This field encompasses a wide range of sub-disciplines and activities, such as the design and development of electrical systems and components and other electrical infrastructure. 

The Project

This circuit is used to detect COVID-19 based on three symptoms: coughing, temperature, and O2 levels. 

1. If no symptoms are detected, the green light should be lit.

2. If one symptom is detected, the yellow light should be lit.

3. If two symptoms are detected, the red light should be lit.

4. If all three symptoms are detected, the alarm should sound.

The circuit uses various logic gates to determine how many symptoms are present and utilizes that information to power the lights and alarm correctly. We also added flip-flops that are regulated by a timer to make our circuit read information at a set interval. This is because the circuit should not be checking for symptoms all the time as there are other temporary causes to the symptoms. For example, one's body may raise in temperature due to exercise. Without the flip-flops, the circuit may read this as a sign of Covid-19. With the addition of flip-flops, the user just has to avoid these possible causes at the intervals when the circuit reads their vitals.

Overall Design Process:

We decided to build the different components of the circuit (alarm, clock, logic) separately and then combine them together in the end. 

Logic Circuit:

The logic circuit was planned out on the whiteboard and comprised of AND, NOT, OR, and XOR gates. The first design didn't work because the yellow and red lights were turning on together in strictly yellow cases. We then re-designed the red light cases in Tinkercad and made sure that it worked before re-building it.

Now came the biggest challenge in creating our logic circuit. Even though all the logic worked out in the Tinkercad, it didn't on our bread board. Through systematic debugging the logic gates, we found that one of the logic gates was inconsistent and was fluctuating between 0 and 1. 

Clock circuit:

The first attempt for the clock circuit resulted in the testing LED shining momentarily before dimming, with no cycle. We concluded that something must have gone wrong with the wiring, so we decided to test the circuit on Tinkercad. 

The first attempt in Tinkercad resulted in a cycle time of 3 seconds, which was too short, so we replaced the 5uF capacitor with a 10uF capacitor, resulting in better cycle time of around 6.5 seconds. With a more concrete visualization of our idea, we were able reliably and physically recreate the circuit with the LED turning on and off every 3.25 or so seconds, which we could then attach to the flipflops on the logic circuit.

Alarm circuit:

The alarm circuit was very straight forward because we had a the blueprint for it. This was the one part of the circuit that we nailed in the first try. :)

Conclusion: Error Analysis

In the end, there were two issues that we did not have time to fix. Firstly, we realized at the end that the switches that we got needed to be grounded AND powered through two pins. We originally thought that they were SPDT so we only grounded the switch. Secondly, we realized that our AND logic gate was fluctuating its output because we were using the wrong voltage/power supply. We only had 3 volts of power when the AND gate required around 4-6V.