Harvard step test

What is Harvard step test?

“The Harvard step test is a type of cardiac stress test for detecting and diagnosing cardiovascular disease. It also is a good measurement of fitness and a person’s ability to recover after a strenuous exercise by checking the recovery rate. The more quickly the heart rate returns to resting, the better shape the person is in.” (wikipedia)

https://www.youtube.com/watch?v=mekPTS_LVv4

The procedure of Harvard step test.

“The person who is taking the test steps up and down on a platform in a cycle of two seconds. The platform is at a height of about 50 cm or 20 inches(usually 16 inches for women). The rate of 30 steps per minute must be sustained for five minutes or until exhaustion. To ensure the right speed, a metronome is used. Exhaustion is the point at which the subject cannot maintain the stepping rate for 15 seconds. The subject immediately sits down on completion of the test, and the heartbeats are counted for 1 to 1.5, 2 to 2.5, and 3 to 3.5 minutes.”(wikipedia)

  • Strategy:  

The professional step testing process is very complicated, and people do not often do step testing, but the recovery of heart rate after exercise is a very important indicator to detect heart health. Although my equipment is not that professional, they can immediately check their physical recovery status when people go to the gym. On the one hand, people have an intuitive understanding of my heart health or physical changes, and they can make corresponding adjustments to the amount of exercise they do.

How does this device work?

The more quickly the heart rate returns to resting, the better shape the person is in, normally heat rate should return to normal within 1 minute after regular exercise.

Test your heat rate after exercise > Your heart rate is very high right after exercise and the red led light up > If your heart rate return to normal the blue led light up > buzzer works as a timer, if your heart rate return to normal within 1 minute you pass the exam.

 

Describe your concept. What sensor would you like to use? What will your device do? Is your design for ☐ Self-reflection or ☐ Self-expression?
How could your design follow the design recommendations?

  • 1)  Instead of representing numbers, represent through materials and aesthetic visuals.

Instead of representing user’s heart rate in number, I used different color of led light as an indicator for people to read. In general, red is a passionately color and blue is a clam color. I choose red and blue leds to send notification to people.

  • 2)  Instead of designing for affect-as-information, design for affect-as-interaction. Treat the biofeedback as a prompt for social interaction or personal self-reflection.
  • I assume it is a self-reflection device because it can immediately check their physical recovery status when people go to the gym. It is a device that reflect people’s health condition.  
  • 3)  Have enough ambiguity that the individual must interpret what the visualization means for themselves.
  • For this project, it can be improved by adding visualization part of this device.
  • 4)  When designing, constantly reflect on how you are making meaning for the individual through your designs. Could you be insinuating that something is negative, unhealthy, etc. ?
  • Since people cannot change the code for this device, they cannot change the heat rate number.
  • 5)  Reflect on the authority you are giving to the biofeedback device. How could you transfer this authority to the individual instead?
  • 6)  Instead of focusing on self improvement, and prescribing an ideal, how could you help individuals with their own personal motivations?
  • For further steps for this project, I want to create a webpage, which can read the number of your heart beat. So people can know their heartbeat in every single time.

Howell, N., Chuang, J., De Kosnik, A., Niemeyer, G., & Ryokai, K. (2018). Emotional Biosensing: Exploring Critical

Alternatives. Proceedings of the ACM on Human-Computer Interaction, 2(CSCW), 69

  • Documentation:

Step1: test heat rate sensor.

I tested both the example code class provided. They all didn’t work at first. Since it is example code, the code is fine and I uploaded the code successfully. I checked the wire connection, port and Arduino board. They all good. After I asked for help, I realize I connect heartbeat sensor in a wrong way:

Most analog sensor with three wires, such as potentiometer, distant sensor. The wire on the sides connect to ground and power, and the one in the middle connect to analog pin. I did the same to heart sensor. I read the instruction on the bag and made it right.

(Left) Green –

(Middle) Yellow +

(Right) Red A0

img_9634

(Heat sensor)

I tested both code and open the serial monitor. Everything works as expected.

Step 2: circuit and wiring

a_bb

(Circuit Diagram without heartsenser)

I used fritzing to make this circuit diagram for leds and buzzer. It is very simple and clear with just two leds(one is red and one is blue). Since I cannot find blue led in fritzing, I used two red leds in the diagram. I also couldn’t find heat rate sensor, so I attach an circuit image below.

img_0331

(Circuit Diagram with Heart Sensor)

Step 3: write Arduino code

I just changed few lines of code of the example code. I used if condition statement and set up a delay time for buzzer.

Code for buzzer:

screen-shot-2019-02-06-at-11-25-07-pm

Code for leds:

screen-shot-2019-02-06-at-11-25-14-pm

Step3: testing in real life

I used it right after aerobic exercise. It worked very well.

The more quickly the heart rate returns to resting, the better shape the person is in, normally heat rate should return to normal within 1 minute after regular exercise.

Test your heat rate after exercise > Your heart rate is very high right after exercise and the red led light up > If your heart rate return to normal the blue led light up > buzzer works as a timer, if your heart rate return to normal within 1 minute you pass the exam.

I tested my heart rate after I went to gym.

  • Insights:
  1. When connecting Arduino board to Arduino IDE, the very first thing you should check is the port name and board name. If you connected to different board. Arduino IDE cannot detect your board and code cannot be uploaded. Both port and board are under Tool at the top of Arduino IDE.
  2. Most analog sensor with three wires, such as potentiometer, distant sensor. The wire on the sides connect to ground and power, and the one in the middle connect to analog pin. I did the same to heart sensor. I read the instruction on the bag and made it right.
  3. Be careful of the led legs. The pin nearest the flat edge will be the negative, cathode pin.

 

  • Information sources:

I added one buzzer into my code and circuit. The buzzer works as a timer.

https://www.instructables.com/id/How-to-use-a-Buzzer-Arduino-Tutorial/

https://www.instructables.com/id/How-to-use-a-Buzzer-Arduino-Tutorial/

 

  • Next Steps: How would you improve upon what you made?

For this project, it can be improved by adding visualization part of this device.