Review of BN2403: Fundamentals of Biosignals and Bioinstrumentation
Year took: AY20/21 Semester 1
BN2403 introduces circuit design, mathematical calculations of components used in bioinstruments, the acquisition of biopotentials from the human body, and how to process them. Arduino Uno and Matlab were used to stimulate the acquisition and processing of biopotentials. BN2403 is a continuous assessment with no final examination. As I took this module during an online semester, my experience may be different from yours. The assessment criteria are as follows:
1. Laboratory report – 20%
- Laboratory report 1 – 10%
- Laboratory report 2 – 10%
2. Quizzes – 40%
- Mid-term quiz – 20%
- Week 13 quiz – 20%
3. Project – 40%
- Project assignments – 20%
- Oral viva – 15%
- Post-module self-reflection – 5%
Weekly two-hour lectures were held on Zoom and were webcast. From weeks 1 to 6, the focus was on circuit design and circuit components such as amplifiers, filters, and sensors. We learned about the usage of these components in medical devices and the calculations behind it. The mathematics expressions were complex, difficult to solve, and confusing as many new variables were introduced. There were many times I struggled to understand the calculations and was lost during lectures. Although the lecture notes contain problem examples, I felt that they were insufficient to illustrate the problem-solving process.
Literally how I be feeling sometimes. (Source)
From weeks 7 to 12, the lectures covered the origin, acquisition, and processing of biopotentials from the body. The lecture content on biopotential origin overlaps with the neural physiology content taught in BN2201. Meanwhile, the lecture on the acquisition of biopotentials introduced ENG, EMG, ECG, ERG, and EEG. In the processing of biopotentials, the basics of Fourier transform, its properties, and convolution were taught. Calculations involving Fourier transform involves integration and differentiation of variables. I found the second half of BN2403 to be as equally challenging as the first half.
Tutorials were 1-hour long and it was held weekly on Zoom. Most tutorial questions were exceptionally tough, and I often struggled to solve them. Eventually, I stopped attempting some of my tutorials because of their extreme difficulty and decided to learn from the tutorial solutions instead. I found the questions difficult because the tutorial tested on concepts that had not been taught. This happened during the first half of BN2403 while we were still learning about instrumentation design and characteristics, but the tutorial tested on circuit calculations that had not been taught.
During tutorials, Prof Huang and Prof James provided a detailed explanation of the answers and patiently answered questions from students. Yet, there were many times when I still could not understand the answers and spent extra time after class to review what was taught.
Two lab sessions were conducted in weeks 5 to 8 and we were grouped in teams of five. The first lab session focused on observing how the gain of an operational-amplifier changes with input and output resistance. Meanwhile, the second lab session analyzed how output voltage changes with input frequency which in turn affects gain.
Before the session, a lab video was uploaded on Luminus which explains the experiment and circuit connections. Thanks to my friend, I knew that we were expected to be familiar with circuit connections before the session. Thus, I noted down how to connect the various circuit components and helped save my group time. The lab reports were not difficult to complete as it was about graph plotting and explaining our observations. However, I felt that the experiments were tedious. For the first experiment, my group’s equipment was faulty thus we changed our oscilloscope and signal generator thrice. Meanwhile, the second experiment required us to take 200 sets of data. My team was exasperated and so relieved that there were only two lab sessions.
The group project commenced on week 9 and we worked with the same team from our laboratory sessions. We had to complete 4 weekly assignments and attend an oral viva on week 13. The focus of the project was on the acquisition of biopotentials using Arduino Uno and processing the biopotentials using Matlab. We were expected to code the Fourier transform concepts we learned from lectures to process the biopotentials in Matlab.
The Matlab code was only provided in assignment 1 and we had to devise the code for the remaining 3 assignments. However, Matlab uses the C++ language for computation and BN2403 did not teach coding. As no one in my group learned C++, we sourced examples online and tried piecing them together to form a working code. Over the weeks, the assignments became increasingly frustrating. We struggled to find suitable examples and did not know how to debug our code because we were unfamiliar with the Matlab interface. We decided to look for the TA, who quickly spotted the problem and provided us with invaluable tips on the usage of Matlab. If your code has any issues, I suggest finding the TA immediately to save time because my group wasted 2 hours trying to debug our code.
On week 13, we had our oral viva. The oral exam was an assessment of our understanding of the weekly assignments. Prof James conducted the oral viva through Zoom and tested each team member individually. We were questioned about the codes we used, the ECG leads arrangement, and the analysis of ECG signals. In preparation for the oral viva, my team compiled a list of possible questions and studied them. I think the oral viva is not difficult if you have a good understanding of the group assignments.
Quiz 1 and Quiz 2
Quiz 1 was held on week 7 and it tested the topics taught from week 2 to week 6. The quiz had 8 questions and they were difficult. I could only solve 3 questions, leaving me demoralized because I could not even complete half of the paper.
This picture captures precisely how I felt. (Source)
After the quiz, I talked to my groupmates and my friends and they shared the same sentiment. To my surprise, I received an email from Prof Huang a few weeks later expressing his satisfaction with the cohort’s performance despite many students struggling with the quiz.
Quiz 2 was held in week 13 and it was a closed book examination. It tested the content taught from week 7 to 12 and I managed to complete most of the quiz. Although it was easier than quiz 1, the quiz was still tough, and I was unconfident of my answers.
All in all, BN2403 is a difficult module. Solving for calculations involving bioinstrumentations requires strong mathematical skills. Moreover, the usage of Matlab required knowledge of C++ which was not taught in the module. The combination of these two factors makes BN2403 demanding.