The following instructable describes a easy to build and inexpensive device to perform pressure measurements and demonstrate Boyle’s law, using the micro:bit in combination with the BMP280 pressure/temperature sensor.
Whereas this syringe/pressure sensor combination has already been described in one of my previous instructables, the combination with the micro:bit is offering new opportunities, e.g. for class room projects.
In addition, the number of descriptions of applications in which the micro:bit is used in combination with a I2C driven sensor are rather limited so far. I hope this instructable might be a starting point for other projects.
The device allows to perform quantitative air pressure measurements, and to display the results on the micro:bit LED array or on a connected computer, for the later using the serial monitor or serial plotter functions of the Arduino IDE. In addition you have a haptic feedback, as you will push or pull the plunger of the syringe yourself, and hereby feel the required power.
By default, the display allows you to estimate the pressure by the level indicator shown on the LED matrix. The serial plotter of the Arduino IDE allows to do the same, but with much better resolution (see video). More elaborate solutions are also available, e.g. in the Processing language. You also can display the precise measured values of pressure and temperature on the LED matrix after pressing the A or B buttons respectively, but the serial monitor of the Arduino IDE is much faster, allowing to display values in near real time.
Total costs and the technical skills required to build the device are rather low, so it could be a nice classroom project under supervision of a teacher. In addition the device could be a tool for STEM projects with focus on physics or used in other projects where a force or weight shall be transformed into a digital value.
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