Circuits

Biomedical Engineering: 

Biomedical engineering is the scientific use of the engineering design process that connects medicine and biology to technology. The applications of this field are mostly in the healthcare field, specifically, in the design of devices such as prosthetics, medical imaging, and implants. 

Electrical Engineering:

Electrical engineers work on the design of all electronic equipment. Their applications are extremely wide since most fields nowadays have implementations that require electric systems.

Series and Parallel Circuits

Series

This series circuit is used to simulate an AND gate. Since both switches need to be closed for the entire circuit to be closed, you must press both for the LEDs to turn on. This circuit illustrated the basic fundamental property of series circuits - if the circuit is broken at any point, current is unable to pass through.




This picture displays the setup which we used to create this circuit. We used a sheet of thin foam to form a base for our components and wired everything from the underside. Unfortunately, we were unable to record the circuit in action, but our observation was that both switches had to be 

Parallel

This parallel is used to simulate an OR gate. Since the single LED is connected in series with a set of two switches in parallel with each other, a throw of either or both switches would turn it on. This is demonstrated by the pictures of the circuit in use, found below.

First switch turns LED on

Second switch turns LED on

Both switches turn LED on

Introduction to Digital Logic and Boolean Algebra

College Readiness Circuit

To get our hands wet with modeling circuits on CircuitLab, we had to make a circuit that uses 1s and 0s to represent if the person took the SAT or the ACT, or a Physical Geology class or a Psychology class. Using OR and AND gates, we made it so the output reveals your college readiness, which is true (1) if you have taken either the SAT or the ACT, and have taken the PG or the Psych class, and is false (0), if you took neither the SAT nor the ACT, or you took neither the PG or the Psych class.

Real CR Circuit

We tried to represent this circuit using real components, but ran into several issues due to our inexperience with switches and breadboards. It wasn't until later that we realized that we had misunderstood the functionality of the SPDT switch, which was making our circuit unreliable.

Corona Virus Detection Circuit

The Goal

Our goal for this section was to create a circuit which simulated a Corona Virus Detection circuit. The concept of the circuit was relatively simple. We had to examine three different 'symptoms' (the input of which was simulated using the same SPDT switches which we had greatly struggled with on day 1, but which we were now able to figure out and use with ease), and based on what combination of these 'symptoms' (namely cough, barf and fever) was being exhibited by the patient, we had to provide a different output. The conditions were as follows:

In order to obtain the most realistic solution, we were to use flip flops to make it so that the symptoms weren't continuously monitored, and were instead monitored at fixed intervals, in order to prevent regular fluctuations in body function from causing false positives, and to make it so the output would remain visible for an extended period of time.

Complete Model

The image above represents the final circuit model which we came up with. Once we had it all charted out using CircuitLab, it was time for us to start working on implementing this physically. We decided that the best way to do it would be to develop each part of the circuit separately in a modular fashion, and then piece everything together once done. This meant that we had three parts which we had to make separately - the logic circuit, the clock circuit, and the alarm circuit.

Alarm Circuit

We used the diagram provided to us to build the alarm component. It was a challenge since most of us had never dealt with resistors and capacitors, but using each other's knowledge, helped us create a functional alarm. The alarm was built using a 555 timing chip, which helped us produce sound of different frequencies.

Clock

For our clock, we first used a calculator to predict our time high and time low, and the value of our required resistors and capacitors. We were then able to use those tools to create our circuit. The LED light was then used to test if the speed of the timing was accurate. Using the calculator, we figured out that the highest possible time between high and low which we could generate was approximately 7 seconds. This time would likely be much longer for an actual monitoring circuit, but for testing purposes, we wanted a time which was both long enough for us to be able to make changes, but short enough for us to be able to test each possible scenario relatively quickly.

Using the CircuitLab software, we modeled the logic unit we will use in our system. We managed to simplify the logic down to 9 gates, which is definitely a good thing since less materials means easier manufacturing.

Logic Circuit Diagram

We realized that using XOR gates we could get a high output when only one out of the inputs was switched on. This was really helpful when it came to the yellow and red lightbulb, since any single input or double input should have a specific output.

Logic Circuit

As we expected, going from the CircuitLab model to a breadboard proved to be a challenge. We encountered several issues, which meant that we had to re-organize our setup, check functionality in each component, and make sure everything was powered. But, using a systematic approach, we built the different modules of the circuit and then tested each one before putting them all together. 

Describing the function of each wire and every gate is pointless, but, basically, the red wires account for the main logic of the red bulb, the yellow wires for the yellow bulb, and the grean ones for the green bulb. This color coordination was very effective when it came to debugging issues.

Week 1 Paper.pdf

Research Paper - Group 1

Designing Circuits

IMG_7714.mov

Video of the circuit!

Final functional circuit

Green  - Logic Unit

Red  - Switches (Representing 3 symptoms) 

Yellow  - Flip Flop (Regulates actualization of LEDs) and LEDs

Blue  - Alarm circuit

Purple - Clock (Powers flip flop every 6-7 seconds)