Disclaimer: The Oximeter you make for this activity should not be used for diagnostic purposes. If at any point you are concerned about your heart rhythm or SpO2 readings, you should consult your physician.
What you need for today's activities
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The Arduino and Cord
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Several Different LEDs
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All the Resistor Strips
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The Pulse Sensor
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Wires
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Seeing your Heartbeat with Light!
The color of blood
Have you ever heard that blood gets darker if it does not have oxygen in it? Well, that's true. The more oxygen blood has, the more deep red light it absorbs so it reflects less deep red.
All sketches for this section come from this source: https://www.youtube.com/watch?v=MHPgamGQmDY
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Graphing blood's light absorption by wavelength
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To the right is a rough sketch showing how much hemoglobin (Hb) absorbs different wavelengths of light depending on if it is oxygenated or not.
Red light at a 660 nm wavelength is used in pulse oximeters because it is the max difference between the two when deoxygenated Hb |
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Your body doesn't block much red light
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ww.researchgate.net/publication/316712743/figure/fig13/AS:668385360744448@1536366896067/a-Tissue-penetration-depth-of-light-with-different-wavelengths-NIR-light-penetrates.png
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https://images.theconversation.com/files/201297/original/file-20180109-83559-19kt3yi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip
Red light can be used to see inside your body.
Well, somethings not right with this finger. Got an xray and yep, something is there.
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All images below are sourced from: http://www.eatonhand.com/img/img00087.htm
Let's shine red light on it. Yep, it's darker where something is sitting.
Click here to see what was taken out after surgery. Warning: somewhat graphic image.
Background: What is a Pulse Oximeter?
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This device checks how well your heart is pumping oxygen through your body.
Oximeters measure oxygen saturation (SpO2). This represents the extent to which hemoglobin is saturated with oxygen. Hemoglobin is protein in red blood cells (RBCs) that binds with oxygen to carry it from your lungs to the tissues of your body. Here is a link to more info on Hemoglobin. |
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It may be used to monitor conditions that can affect blood oxygen levels.
Some of these conditions include:
Some of these conditions include:
- chronic obstructive pulmonary disease (COPD)
- asthma
- pneumonia
- lung cancer
- collapsed lung
- pulmonary embolism
- anemia
- heart attack or heart failure
- Sleep apnea
- congenital heart defects
(You can click on each of these to learn more)
Video Lesson about Blood Oxygen
Please watch this short video from RCC nursing on the basics of blood oxygen.
Video Pending:
Video Pending:
