Measuring the Heart BeatHere is a video that shows a similar sensor to what you will build. This way, you know what to expect. We will use a sensor to get a plot of our heartbeat. Specifically, the sensor measures the IR light going through/off your skin. As blood pumps, this value changes.
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In this activity, we will turn on a light every time your heart beats. In order to do this, you need to set a "threshold value". That means a limit. The light is kept on whenever your sensor gets a reading below that point and the graph goes below that point. If it is outside that value, the light will be off. For my above graph, you can see that the graph goes between 104,100 and 103,500. It quickly drops down to the 103,500 value when my heart beats. Your value will be different, so you need to look at your graph to pick this number.
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If your sensor is powered correctly, you should see a little red light on it. If you do, put your thumb over the sensor and keep it there. After several seconds, it should level out your BMP reading.
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