This is not a medical instrument, that is why it is listed under toys. It is fun to compare the blowing power of different people. The airstream will rotate a fanblade linked to the shaft of a small DC motor, which acts as a generator. The current charges a capacitor. To prevent dischargeing over the DC motor, a diode is inserted. In this way, if you have a capacitor with low leak, the value can be measured more easily. The output voltage is in the order of 5 volts. Instead of using a multimeter, a led scale can be applied as well.
A push button over the capacitor discharges the capacitor and the circuit is than ready for a new measurement. By replacing the two resistors by a 5K trimpotentiometer, the sensitivity can be changed. A box design is up to you.
Every Thursday is #3dthursday here at Adafruit! The DIY 3D printing community has passion and dedication for making solid objects from digital models. Recently, we have noticed electronics projects integrated with 3D printed enclosures, brackets, and sculptures, so each Thursday we celebrate and highlight these bold pioneers!
Have you considered building a 3D project around an Arduino or other microcontroller? How about printing a bracket to mount your Raspberry Pi to the back of your HD monitor? And don’t forget the countless LED projects that are possible when you are modeling your projects in 3D!
The Adafruit Learning System has dozens of great tools to get you well on your way to creating incredible works of engineering, interactive art, and design with your 3D printer! If you’ve made a cool project that combines 3D printing and electronics, be sure to let us know, and we’ll feature it here!