Category: Austin Lin’s Status Reports

This week I finished up the final presentation and also attended and provided feedback on the final presentations for other groups (6 hrs). I also put finishing touches on the hardware box. This involved braiding and crimping a long wire for the heart rate sensor. I devised a system for ensuring that pulling on the heart rate sensor wire wouldn’t pull the wire out of connections in the box. I did this by tying a knot in the wire and threading the wire through a nut so that if the wire was pulled this motion would be stopped when the knot met the bolt. I also added a battery to the box to make it portable and added a switch to exterior to turn the battery supply on and off. Holes were drilled into the exterior for the switch and heart rate sensor wires to come out of.

Plan for next week: Work on final report

This week I finished working on the design of the housing and layout, and wiring of the belt clipped device and I drew a schematic of the wiring in my favorite drawing software (see Exhibit A) I purchased the arduino shield and connectors. I also finished building the belt clipped device (see Exhibit B). This was where the bulk of my time was spent this week.

I started out by cutting a square hole for the ardunio programming cable. This took a very long time as I had to measure exactly where to put the hole and cut it out using an x-acto knife. In the beginning, I had a very hard time crimping the wires correctly to place into the connector. After crimping the wires, connecting them to the breadboard and into the terminal blocks was pretty quick. I estimate this entire process took me around 6 hours.

Next week, I will finish the final presentation, start putting the final touches on the prototype, and start working on the final report.

EXHIBIT A

EXHIBIT B

This week I worked with my team on integration of the Arduino and the Desktop application via bluetooth. This was complicated by the fact that our bluetooth chip burnt up unexpectedly. We were able to acquire a new one before our interim demo. I also prepared for our interim demo by practicing what I was going to say and also listening to Lev and David’s parts for interim demo.

This week I will work with the students in the Electronic Fabrication Lab to get the HR sensor resoldered and also help lev and david with integration of Smart contract with the desktop application.

We are on schedule 🙂

This week I worked on bluetooth transmission. I found a java script that can receive bluetooth signals on windows laptops and was able to send and receive data to/from the arduino board. After proving that the example from the internet worked, I worked on implementing this in our arduino code. Sending data was pretty easy. However, receiving data proved to be quite complex since the data is sent one character at a time. It was very difficult to get the Arduino to process each character into a string. I kept getting an empty string or a string with just one character. Eventually I was able to do get the entire string after searching for a “\n” at the end of the string.

In other news, I did not solder our heart rate sensor very well and it broke on Wednesday. We ordered 2 more. Hopefully, they will arrive before our interim demo.

Lev also told me that our bluetooth module stopped working and we placed an order for 5 more. I will attempt to also secure one from another group.

My plan for this week is to clean up my arduino code and help David and Lev with integration with smart contracts.

This week my goals were to get the HR sensor and Bluetooth transmission working.

First, I decided to modify my code from last week to take the magnitude of acceleration in order to determine the overall acceleration and to account for the acceleration due to gravity.

I wrote the code to package the data for bluetooth transmission. Testing the bluetooth transmission was quite difficult. There were many tutorials online that involved using a phone app to receive and send bluetooth data to the arduino. I was not able to find an app on the apple app store that could easily identify the arduino’s bluetooth chip. All the apps listed the chips UUID and since there are hundreds of bluetooth devices in the vicinity at any point on campus it was impossible to determine which UIUD was associated with the Arduino. I found a tutorial this afternoon that used a Windows PC to communicate with the Arduino. I was able to acquire a windows PC tonight but have not had a chance to test it out.

The HR sensor code writing was relatively smooth. Soldering the wires on to the sensor was pretty difficult though since the sensor is so small.

My current goals for this week are to work with my teammates to integrate the arduino with the desktop app. David has not updated me on his progress with the desktop app so this goal is assuming that the desktop app is complete. If the desktop app is incomplete, I will help him to finish the desktop app so it is ready for integration.

This week I worked on the code to pull acceleration data from the arduino and on the ethics assignment.

Interpreting the acceleration data proved to be a bit difficult. All of the code samples I found online for how to use the sensors were incomplete.  The acceleration data was sent to the Arduino’s analog inputs using a scaled voltage. The first code sample I found only read the scaled voltages and did not apply any manipulations to the voltages, so it was confusing when I was getting readings in ~300-400 range. It required a bit of data sheet digging to figure out how exactly the scaled voltage corresponded to an acceleration measurement. After writing the code to map the range of voltage values to force in G’s, I noticed that the G force was a bit off. I expected 1G due to earth’s gravitation field but I was getting ~0.7g. I used a calculator to verify that my mapping equation was correct and that I just needed to recenter the mapping so that the voltage mapped to 1G instead of 0.7g.

I am a bit behind schedule. The ECG sensor and HR sensor didn’t arrive until Friday, so I was not able to start working on the code to pull data off the ECG sensor/HR sensor.

Next week, I will work on writing the code to pull HR data off the HR sensor and work on writing the code for BT transmission to the desktop application.

Most of my time this week was spent practicing for the design review presentation. I have to practice a lot in order to not feel nervous for presentations. I’m always very envious of people who can just get up and give impromptu speeches and presentations because I could never do that.

Time breakdown:
Approximately 1.5 hours was spent trying to figure out how to cut our design presentation down to 15 minutes. My early practices were around 20-25 minutes per presentation. I practiced my presentation 8+ more times to be certain that I would be able to give a smooth delivery during the actual presentation. I estimate this to take at least 2.25 hours since each presentation is 15 minutes and accounting for time to take notes between each presentation.

4 hours was spent in class. This week in class I watched and gave comments on other team’s design reviews. I’m pretty confident I gave good comments on Monday. On Wednesday, I was very nervous since I was presenting last and had a hard time concentrating on the presentations because of it and this may have impacted the quality of my comments to the Wednesday teams.

1 hour was spent in a team meeting to discuss plans to complete the design review.

The remaining time this week was spent working on writing the design review.

I am on schedule.

This week I worked on the hardware design of our system. I speced out the ECG sensor, wireless receiver for the ECG sensor, and accelerometer and placed orders for them (2 hours). I also did research into how to connect each pin of the sensors to an arduino (2 hours) to generate preliminary schematics of the system (3 hours). Getting all the wires and components arranged neatly took a very long time with my drawing software.

I also helped out with the design presentation. Specifically, the following slides:

• Introduction and Use Cases
• Hardware Specification
• Hardware – uECG
• Hardware Circuits – Belt Clipped Device

I am on schedule. This week was devoted to specifying the entire system. I was responsible for hardware and specifications for the hardware system is complete.

As of right now, I am giving the design presentation. Thus, I will spend some time this week practicing the presentation. This next week I plan to start writing the code for the arduino to pull data off the sensors as a proof that the sensors will work for the project. If there is time left over, I will start integrating each sensor together into one big arduino program and figure out how to send the data over bluetooth to the desktop application.

This week I helped to create a proposal presentation (specifically the Use Case Requirements and Solution Approach and MVP slides) which was presented by Lev Stambler.  I also watched the proposal presentations for the other groups and provided feedback on them. I also researched the frameworks we planned to use this week, such as Raspberry Pi and Jetson.

My progress is on schedule. This week was dedicated to creating proposal and researching the frameworks we plan to use.

Next week we will continue to research frameworks and also start developing a mockup of a desktop app.