“Hello there, hope you are doing good and in this tutorial I will be showing you how i made a current sensor for Arduino using some very basic electronic components and a home-made shunt. This shunt can easily handle large magnitude of current, around 10-15 Amps. The accuracy is also pretty good and I was able to get very decent results while measuring low currents around 100mA.
Supplies:
Arduino Uno or equivalent and programming wire
OP- Amp LM358
Jumper wires
100 KOhm resistor
220 KOhm resistor
10 Kohm resistor
Veroboard or Zero PCB board
Shunt(8 to 10 milliohms)
The main parts you would need for this build is a Shunt along with the operational amplifier IC. For my application I am using the IC LM358 which is a dual OP-AMP 8 pin DIP IC of which I am using only one of the operational amplifier. You will also be needing resistors for the Non-inverting amplifier circuit. I have chosen 320K and 10K as my resistances. The choice of your resistance completely depends upon the amount of gain you want to have.Now the OP-AMP is being powered by the 5 volt of the Arduino. So we need to make sure that the output voltage from the OP-AMP when the full current is passing through the shunt should be less than 5 volts, preferably 4 volts to keep some margin of error. If we choose a gain which is very high enough then for a lower value of current, the OP-AMP will go into saturation region and only give 5 volts beyond any current value.So be sure to choose the value of amplifier gain appropriately. You would also require a prototyping PCB or breadboard to try this circuit. For the micro controller I am using the Arduino UNO to acquire the input from the amplifier output. You can choose any equivalent Arduino board you want.”