Fidget Spinner RPM Meter

When the fidget spinners rushed into the world obviously my kids wanted them as well.

It didn't take much time to throw the question to myself, "what is the max speed I can make with them"?

The main ingredients:

-PIC16F882 microchip

-Infra sensor

-HC-05 Bluetooth module

-Android app with MIT app inventor

The infra LED makes invisible light, when the fidget spinner's arm goes above it, it reflects the light back to the infra detector.

The microcontroller detects this and count the time between the arms.

Via Bluetooth the chip sends the data to the mobile phone and the app shows that on the screen.

Because fidget spinners have different amount of arms, I gave option in the app to select the number of the arms for the most precise result.