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. https://youtu.be/VyUaCc8frQk
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!
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.