Question

Assignment 3: EECE 7101 Embedded System Design Design an Arduino based system to measure from – 100V to +100V. Show the design calculations and basic diagram. Consider that the Arduino can convert OV to +5V analog voltage only to digital signal.

Answer 1

Let's focus on Arduino features . It have in built Adc. So if the voltage lies between 0 to 5 volt then it will measure the voltage .

The Adc is of 10bits . So the resolution will be 5/2¹⁰=4.9mv

now our main aim is if we can map -100 volt to 100volt between 0 to 5 volt then our work can be done easily.

so from the image it is clear that it the value of vx will be between 0 to 200 volt

There is resistor divider circuit is there .so at non inverting input the voltage= v_{​​​​x​​​}​​​ x 5/(5+195)

V+= V_{​​​​​​x}/40

So opamp output will be V+ because it is a voltage follower

so using ADC of Arduino at analog pin it will convert V+ to digital format

Vdigital=V+/1024

V+ = Vdigital x 1024

V_{​​​​​​x}​​​/40 =Vdigital x 1024

V_{​​​​​​x}=Vinput +100Volt

Vinput=40960 x Vdigital-100volt

So using this procedure we can measure the voltage between-100 to 100