16x2 LCD nearly works - but has a few strange characters. Why???
hi everyone,
i beginner please excuse lack of knowledge how lcd's work (let alone i2c lcd's).
project aim:
display serial number of rfid tag onto 16x2 i2c lcd.
hardware:
1) arduino uno smd r2;
2) innovations id-20la rfid reader , 1 rfid card (to wave in front of it);
3) 16x2 serial clear victory 1602-1 lcd module i2c backpack (gy-iiclcd). both cheap off ebay;
software:
1) arduino ide 1.0.5 (and use serial monitor display rfid card number);
2) new liquidcrystal library (by f malpartida).
what happens:
when wave rfid card in front of rfid reader, beeps indicate successful read, rfid card number displayed via serial monitor correctly, when appears on lcd screen has 1 x strange character before it, , 3 strange characters after it. the actual rfid number in between strange characters correct however.
my code:
as new, found 2 pieces of code , put them try , achieve aim - did not write of it. i assume there problem in way have combined 2 sketches. code below:
any feedback appreciated.
i have attached photo of lcd screen looks (note single garbage character before , 3 garbage characters after correct rfid card number).
best regards
john
i beginner please excuse lack of knowledge how lcd's work (let alone i2c lcd's).
project aim:
display serial number of rfid tag onto 16x2 i2c lcd.
hardware:
1) arduino uno smd r2;
2) innovations id-20la rfid reader , 1 rfid card (to wave in front of it);
3) 16x2 serial clear victory 1602-1 lcd module i2c backpack (gy-iiclcd). both cheap off ebay;
software:
1) arduino ide 1.0.5 (and use serial monitor display rfid card number);
2) new liquidcrystal library (by f malpartida).
what happens:
when wave rfid card in front of rfid reader, beeps indicate successful read, rfid card number displayed via serial monitor correctly, when appears on lcd screen has 1 x strange character before it, , 3 strange characters after it. the actual rfid number in between strange characters correct however.
my code:
as new, found 2 pieces of code , put them try , achieve aim - did not write of it. i assume there problem in way have combined 2 sketches. code below:
code: [select]
/* yourduino.com example software sketch
16 character 2 line i2c display
new type marked "arduino-iic-lcd gy-lcd-v1"
terry@yourduino.com */
/*-----( import needed libraries )-----*/
#include <wire.h>
#include <lcd.h>
#include <liquidcrystal_i2c.h> // f malpartida's newliquidcrystal library
#include <softwareserial.h>
softwareserial id20(3,2); // virtual serial port
char i;
/*-----( declare constants )-----*/
#define i2c_addr 0x20 // define i2c address pcf8574a
//---(following pcf8574 pin assignments lcd connections )----
// different earlier/different i2c lcd displays
#define en_pin 4
#define rw_pin 5
#define rs_pin 6
#define d4_pin 0
#define d5_pin 1
#define d6_pin 2
#define d7_pin 3
/*-----( declare objects )-----*/
liquidcrystal_i2c lcd(i2c_addr,en_pin,rw_pin,rs_pin,d4_pin,d5_pin,d6_pin,d7_pin);
void setup() /*----( setup: runs once )----*/
{
lcd.begin (16,2); // initialize lcd
serial.begin(9600);
id20.begin(9600);
}// end setup
void loop() /*----( loop: runs on , on again )----*/
{
// reset display
if(id20.available())
{
i = id20.read(); // receive character id20
serial.print(i); // send character serial monitor
lcd.print(i);
}
} // end loop
any feedback appreciated.
i have attached photo of lcd screen looks (note single garbage character before , 3 garbage characters after correct rfid card number).
best regards
john
it looks you've done job of getting lcd communicate , display. suspect serial input source of garbage characters.
have checked output = id20.read(); // receive character id20 ?
are garbage characters same? check incoming string , ignore characters or ignore characters not alpha-numeric?
have checked output = id20.read(); // receive character id20 ?
are garbage characters same? check incoming string , ignore characters or ignore characters not alpha-numeric?
Arduino Forum > Using Arduino > Displays > 16x2 LCD nearly works - but has a few strange characters. Why???
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