monitor breathing

Is your breathing steady while you sit restfully? How does it change when you talk? How does it change when you exercise? How quickly do you recover after exercise? To find out you can monitor your breathing movements with the computer. Your chest movements cause changes which are monitored by a sensor and sent to the computer.

There are several ways to monitor the movements of your chest. You can use a position sensor and a spirometer box – and this works well. Or you can use a specially made sensor called a breathing sensor which is worn around the chest. One type is a breathing (stretch) sensor and another is called a stethograph which is used with a pressure sensor.
You can start this investigation by taking some readings at rest, and looking at the graph patterns.

What to do
Choose your breathing sensor or stethograph, plastic tubing and a pressure sensor. Connect the sensor to a socket on the interface.
Attach the belt around the chest. Wear it such that it does not restrict breathing or slip. If your sensor has range settings, set it to work over a narrow range.
Start your sensing software. Some systems will automatically recognise the sensor you attach, in others you have to set up the software to do this. Get your software to record for a minute.
Do a test run and, if the sensor is adjustable, adjust it to get the reading on the screen.
Now investigate how your breathing changes during different activities.

Questions about your experiment

• Count the number of peaks to work out the respiration rate.
• Zoom in on a good part of the graph. Which part of each peak is inspiration?
• Does the ‘expiration’ part show the same shape as this, if not why not?
• Do the shapes of the peaks look different after exercise?
• Does it matter where you attach the belt on the torso?
• Teacher question: some sensors record the breathing rate as opposed to showing the chest movements. Which do you find more useful?