Make Arduino UNO Voltmeter Within 2 Minutes!

1float input_volt = 0.0;
2float temp = 0.0;
3float r1 = 33000.0;
4float  r2 = 840000.0;
5
6void setup()
7{
8  Serial.begin(9600);
9}
10
11void  loop()
12{
13
14  int analogvalue = analogRead(A2);
15  temp = (analogvalue  * 5.0) / 1024.0;
16  input_volt = temp / (r2 / (r1 + r2));
17  if (input_volt  < 0.1)
18  {
19    input_volt = 0.0;
20  }
21  Serial.print("Volts =  ");
22  Serial.println(input_volt);
23
24  delay(100);
25
26
27}

1float input_volt = 0.0;
2float temp = 0.0;
3float r1 = 33000.0;
4float
5  r2 = 840000.0;
6
7void setup()
8{
9  Serial.begin(9600);
10}
11
12void
13  loop()
14{
15
16  int analogvalue = analogRead(A2);
17  temp = (analogvalue
18  * 5.0) / 1024.0;
19  input_volt = temp / (r2 / (r1 + r2));
20  if (input_volt
21  < 0.1)
22  {
23    input_volt = 0.0;
24  }
25  Serial.print("Volts =  ");
26
27  Serial.println(input_volt);
28
29  delay(100);
30
31
32}