Voltage Sensors :
5V = ADC count 1024
1 ADC count = (5/1024)Volt= 0.0048828Volt
Vin = Vout*(R1+R2)/R2 R1=100 and R2=20
Vin= ADC count*0.00488*(120/20) Volt
As per seller information for ACS 712 current sensor
Sensitivity is =100mV / A =0.100V/A
No test current through the output voltage is VCC / 2= 2.5
ADC count= 1024/5*Vin and Vin=2.5+0.100*I (where I=current)
ADC count= 204.8(2.5+0.1*I) =512+20.48*I
=> 20.48*I = (ADC count-512)
=> I =(ADC count/20.48)- 512/20.48
Current (I) =0.04882*ADC -25
More details on ACS712
Temperature Sensor :
As per data sheet of LM35
Temp in deg C =(5/1024)*ADC count*100
Note : The sensors are calibrated by assuming the arduino Vcc= 5V reference.But in practical it is not 5V always.So there may be chance of getting wrong value from the actual value.It can be solved by following way.
Measure the voltage between arduino 5V and GND by a multimeter.Use this voltage instead of 5V for Vcc in your code.Hit and try to edit this value until it matches the actual value.
Example: I got 4.47V instead of 5V.So the change should be 4.47/1024=0.0043652 instead of 0.0048828.
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