Digital Protractor

- An Interesting DIY Idea ..

What if Your Ruler Scale converted in to Protractor .....

This Project is all about convert an ordinary ruler in to Smart Ruler having a extra feature of measurement of Angle.

Step 1 :- What you need

other handy tools -

Step 2: How It Works..

Heart of this module here is ARDUINO PRO MINI , It is use here to handle all external Peripherals like ButtonPanel, OLED display and Gyroscope(MPU6050).

  • To Power up this module here we use 3.7v Lippo Battery which is capable to deliver upto 180mAH,to charge battery here TP4056 module used via 3pin Toggle Switch.
  • Here Gyroscope send raw data to Pro mini, by mathamatical calculation Arduino Pro mini find YAW ANGLE from it based on movement of scale(ruler) on which this module is sticked.
  • OLED display here use to display current angle with respected to taken refrence using button_2.
  • OLED and Gyrscope(MPU6050) use I2C Protocol to interface with Arduino Pro MINI.

Lets understand Button function:

Button_1 : Press to enter into Angle mode to measure angle.

Button_2 : for taking Reference form which you have to measure angle.

Button_3: for calibration of Module (In case of Temperature and humidty variation).

for better understanding see video of Working of Digital_Protector .

Toggle Switch :

Toggle Switch has two mode ON and OFF mode.

ON mode: To turn on module and measure angle.

OFF mode : 1) To turn off module

2) To charge module

[ NOTE: Don`t use ON mode for Charging It may Damage Your Hardware. ]

Step 3: Circuit Building


  • Make all connection as per shown in circuit daigram with compactness because we are fitting all circuit in plastic Box in order to make module very compact.
  • One thing is you need to take care about Yourself how to fit all electroincs stuff in plastic box because here I didn`t mention anyware how to fit all stuff in box.
  • [ Note : So, make connection as small as possible in to order to fit in the Plastic Box.]


Step 4: Firmware Uploding ...

> Connect arduino NANO to host computer

> open Sketchbook of firmware in Arduino IDE

>Select COM port.

> Upload Code and Play with Digital Protector.

[Note : Keep all files in one folder as a scketchbook in order to sucessfully code uploading.]

Future Scope :-

As Arduino is Open source[thanks !] so developed a board where all connection is on board you have to just solder it and play ! yayy...

Thanks for Reading !...