Anyone know what happen to my lcd display?

Other Hardware Displays
1

Please help me out about what happen to the display?

Why there has garbled character after 6cm?

After few runs the display comes out many garbled characters then frozen.

#include <NewPing.h>
#include <LiquidCrystal.h>
#define TRIGGER_PIN  8  
#define ECHO_PIN     9  
#define MAX_DISTANCE 200 
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); 

void setup() {
  lcd.begin(16, 2);
  lcd.clear();
}

void loop() {
  delay(500);                      
  unsigned int uS = sonar.ping(); 
  
  lcd.print("Ping: ");
  lcd.print(sonar.convert_cm(uS));
  lcd.println("cm");
  delay(500);
  lcd.clear();
}
2

Did you ground the C/D-pin on the display?

Show us a schematic.

// Per.

3

Zapro:
Did you ground the C/D-pin on the display?

Show us a schematic.

// Per.

The display connection I just follow the book and do some modification hide some cables under the display.

4

According to your code:
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

I assume your LCD control pins is the same as Hello World demo program. listed as below:
The circuit:

  • LCD RS pin to digital pin 12
  • LCD Enable pin to digital pin 11
  • LCD D4 pin to digital pin 5
  • LCD D5 pin to digital pin 4
  • LCD D6 pin to digital pin 3
  • LCD D7 pin to digital pin 2
  • LCD R/W pin to ground
  • LCD VSS pin to ground
  • LCD VCC pin to 5V
  • 10K resistor:
  • ends to +5V and ground
  • wiper to LCD VO pin (pin 3)

so, I think you need connect LCD module pin 5 (R/W) to GND, and in you vedio YOUR E pin should connect to LCD module pin 6, not pin7 D0!

5

chincheng:
According to your code:
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

I assume your LCD control pins is the same as Hello World demo program. listed as below:
The circuit:

  • LCD RS pin to digital pin 12
  • LCD Enable pin to digital pin 11
  • LCD D4 pin to digital pin 5
  • LCD D5 pin to digital pin 4
  • LCD D6 pin to digital pin 3
  • LCD D7 pin to digital pin 2
  • LCD R/W pin to ground
  • LCD VSS pin to ground
  • LCD VCC pin to 5V
  • 10K resistor:
  • ends to +5V and ground
  • wiper to LCD VO pin (pin 3)

so, I think you need connect LCD module pin 5 (R/W) to GND, and in you vedio YOUR E pin should connect to LCD module pin 6, not pin7 D0!

You're right. My E pin connected to 7. Thanks

The frozen issue has been fixed after I switch the E pin back to 6.

However, still has that garbled character after the world "cm".

6

Did you connect R/W pin to GND?

7

chincheng:
Did you connect R/W pin to GND?

yes, I did. Pin 5 to GND

8

Chnage the lcd.println("cm"); to lcd.print("cm");

9

chincheng:
Chnage the lcd.println("cm"); to lcd.print("cm");

WOW. All fixed. Thank you.

10

I'm so happy for you!