Ohm meter with Arduino Uno

1/*
2The program reads the analog values of A0. These values are in the   range of 0-1023. 
3*/
4
5#include <LiquidCrystal_I2C.h>
6#include <LCD.h>
7
8#define   analogInput A0
9#define R1 220
10#define vin 5
11#define BACKLIGHT_PIN 3
12#define   En_pin             2
13#define Rw_pin             1
14#define Rs_pin             0
15#define   D4_pin             4
16#define D5_pin             5
17#define D6_pin             6
18#define   D7_pin             7
19
20LiquidCrystal_I2C lcd(0x27, En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin);
21
22void   setup() {
23 
24  Serial.begin(9600); 
25  
26}
27
28void loop() {
29  int   sensorValue=analogRead(analogInput);
30  float voltage=sensorValue*(5.0/1023.0);
31   screen(String(resistance(voltage)));
32  delay(3000); 
33}
34
35int resistance(float   vout){
36  return R1*(1/(vin/vout-1));
37}
38
39void screen(String text){
40   //Define the LCD as 16 column by 2 rows 
41    lcd.begin (16,2);
42    
43     //Switch on the backlight
44    lcd.setBacklightPin(BACKLIGHT_PIN,POSITIVE);
45     lcd.setBacklight(HIGH);
46    
47    //goto first column (column 0) and first   line (Line 0)
48    lcd.setCursor(0,0);
49    
50    //Print at cursor Location
51     lcd.print("Resistor value is: ");
52
53    //goto second column and first   line
54    lcd.setCursor(0,1);
55    lcd.print(text);
56    lcd.print(" ohm");
57   
58}

1/*
2The program reads the analog values of A0. These values are in the  range of 0-1023. 
3*/
4
5#include <LiquidCrystal_I2C.h>
6#include <LCD.h>
7
8#define  analogInput A0
9#define R1 220
10#define vin 5
11#define BACKLIGHT_PIN 3
12#define  En_pin             2
13#define Rw_pin             1
14#define Rs_pin             0
15#define  D4_pin             4
16#define D5_pin             5
17#define D6_pin             6
18#define  D7_pin             7
19
20LiquidCrystal_I2C lcd(0x27, En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin);
21
22void  setup() {
23 
24  Serial.begin(9600); 
25  
26}
27
28void loop() {
29  int  sensorValue=analogRead(analogInput);
30  float voltage=sensorValue*(5.0/1023.0);
31  screen(String(resistance(voltage)));
32  delay(3000); 
33}
34
35int resistance(float  vout){
36  return R1*(1/(vin/vout-1));
37}
38
39void screen(String text){
40  //Define the LCD as 16 column by 2 rows 
41    lcd.begin (16,2);
42    
43    //Switch on the backlight
44    lcd.setBacklightPin(BACKLIGHT_PIN,POSITIVE);
45    lcd.setBacklight(HIGH);
46    
47    //goto first column (column 0) and first  line (Line 0)
48    lcd.setCursor(0,0);
49    
50    //Print at cursor Location
51    lcd.print("Resistor value is: ");
52
53    //goto second column and first  line
54    lcd.setCursor(0,1);
55    lcd.print(text);
56    lcd.print(" ohm");
57  
58}