This device  is very simple and easy to make and contains the following components:

        - Arduino Nano microcontroller
        - 16x2 LCD display
        - LM317 voltage regulator
        - Potentiometer
        - and resistor 12 Ohm

  It consists of constant current source of 100mAmp. Constant current source is built using LM317:

    Iconst = Vref / R where: Vref of LM317 is 1.25V
    Iconst = 1.25 / R
    Iconst = 104mAmp

  Measuring voltage drop across a resistor having constant current gives us resistance value (R = V / I), Where:

   I = 100mAmp as we are using constant current source of 100mAmp
   V = Measured by Arduino  

  This code and circuit will not work for values more than 50 Ohm as 50 * 100mA = greater than 5V.
      The accuracy of this Milliometer is satisfactory and mostly depends on the accuracy of the 12 ohm resistor and the stabilized voltage of 5 volts. Finally, the device is placed in a suitable box and is another useful tool in your laboratory.