Hello;
I am searching for an Arduino LCD shield, but I need also to use at least 2 i/o digital signals of my Arduino board.
What shields do you recommend?
I've had a looked at the arduino shield of dfrobot: http://www.cooking-hacks.com/index.php/lcd-shield-for-arduino.html
Does anybody expierience in this device?
Thanks a lot
Anton
TLERDRDEN:
Hello;
I am searching for an Arduino LCD shield, but I need also to use at least 2 i/o digital signals of my Arduino board.
What shields do you recommend?
I've had a looked at the arduino shield of dfrobot: http://www.cooking-hacks.com/index.php/lcd-shield-for-arduino.html
Does anybody expierience in this device?
Thanks a lot
Anton
I have that device, and I've used it a few times and it works. Right now, the project I'm working on doesn't use a screen, so I've only done some tests with it. The original version of the shield evidently was mis-wired in that you could not control the brightness, and some vendors had the warning not to use pin 10 at atll. When I bought mine, it had been fixed. Here was my initial post about the screen: Is there a shield for extra power + display? - Project Guidance - Arduino Forum
Since then, I've learned that it wasn't a power issue for the servo (though that can be a problem if you use anything by a single low powered hobby servo). The issue is that the Servo library disables PWM on pins 9 and 10 even if you don't have a servo on those pins, and the LCD wants to use those pins as PWM. So, if you never plan to use a servo, the screen would work.
One thing in using it, I've come to the conclusion that 16x2 is a rather small size for doing I/O. Here is a LCD screen I've been thinking of that has a 20x4 screen, keypad, buzzer, sensor I/O ports, real time clock + holder for battery, and ability to mount an EEPROM for larger data collection: http://www.ebay.com/itm/221120816817?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649
Here is a sample code that I cobbled together that uses the buttons to control the screen brightness using the LiquidCrystal library:
// Standard output pin assignments
// Pin 0: serial receive (usb)
// Pin 1: serial transmit (usb)
// Pin 2: Interrupt 2 via attachInterrupt
// Pin 3: Interrupt 3 via attachInterrupt, 8-bit PWM output via analogWrite
// Pin 4: No special use
// Pin 5: 8-bit PWM output via analogWrite
// Pin 6: 8-bit PWM output via analogWrite
// Pin 7: No special use
// Pin 8: No special use
// Pin 9: 8-bit PWM output via analogWrite
// Pin 10: 8-bit PWM output via analogWrite, SPI SS
// Pin 11: 8-bit PWM output via analogWrite, SPI MOSI
// Pin 12: SPI MISO
// Pin 13: On board LED, SPI SCK
// Standard input pin assignments
// Pin A0: No special use
// Pin A1: No special use
// Pin A2: No special use
// Pin A3: No special use
// Pin A4: TWI SDA pin (Wire library)
// Pin A5: TWI SCL pin (Wire library)
// LCD shield pin assignments
// Output pin 4, 5, 6, 7, 8, 9 and 10
// Input pin A0.
#include <LiquidCrystal.h>
// select the pins used on the LCD panel
LiquidCrystal lcd (8, 9, 4, 5, 6, 7);
const int pin_button = A0;
const int pin_led = 13;
const int pin_brightness = 10;
const int max_brightness = 255;
const int min_brightness = 1;
const int delta_brightness = 1;
const int delta_brightness2 = 10;
const int col_brightness = 11;
const int row_brightness = 1;
int cur_brightness = (min_brightness + max_brightness) / 2;
const int col_header = 0;
const int row_header = 0;
const int col_key = 0;
const int row_key = 1;
const int delay_key = 250;
const int delay_debounce = 50;
const int button_right = 0;
const int button_up = 1;
const int button_down = 2;
const int button_left = 3;
const int button_select = 4;
const int button_none = 5;
static int old_key = button_none;
static unsigned long prev_millis = 0UL;
// Key message
char msgs[][7] = {
"Right ",
"Up ",
"Down ",
"Left ",
"Select",
};
// adjust the brightness
static void
adjust_brightness (void)
{
analogWrite (pin_brightness, cur_brightness);
lcd.setCursor (col_brightness, row_brightness);
lcd.print (cur_brightness);
if (cur_brightness < 10)
lcd.print (" ");
else if (cur_brightness < 100)
lcd.print (" ");
}
// read the buttons
int
read_LCD_buttons (void)
{
int adc_key_in = analogRead (pin_button); // read the value from the sensor
// my buttons when read are centered at these valies: 0, 144, 329, 504, 741
// we add approx 50 to those values and check to see if we are close
// We make this the 1st option for speed reasons since it will be the most likely result
if (adc_key_in > 1000)
return button_none;
if (adc_key_in < 50)
return button_right;
if (adc_key_in < 195)
return button_up;
if (adc_key_in < 380)
return button_down;
if (adc_key_in < 555)
return button_left;
if (adc_key_in < 790)
return button_select;
return button_none;
}
void
setup (void)
{
pinMode (pin_led, OUTPUT); // we'll use the debug LED to output a heartbeat
digitalWrite (pin_led, LOW);
lcd.begin (16, 2); // start the library
lcd.clear ();
lcd.setCursor (col_header, row_header);
lcd.print ("Push the buttons"); // print a simple message
lcd.setCursor (col_key, row_key);
lcd.print ("<none>");
pinMode (pin_brightness, OUTPUT);
adjust_brightness ();
}
void
loop (void)
{
int key, key2;
unsigned long cur_millis = millis ();
key = read_LCD_buttons ();
delay (delay_debounce); // wait for debounce time
key2 = read_LCD_buttons ();
if (key == key2 && (key != old_key || ((cur_millis - prev_millis) >= delay_key)))
{
if (key == button_none)
{
digitalWrite (pin_led, LOW);
lcd.setCursor (col_key, row_key);
lcd.print ("<none>");
}
else
{
int prev_brightness = cur_brightness;
digitalWrite (pin_led, HIGH);
lcd.setCursor (col_key, row_key);
lcd.print (msgs[(int)key]);
if (key == button_down)
cur_brightness -= delta_brightness;
else if (key == button_up)
cur_brightness += delta_brightness;
else if (key == button_select)
cur_brightness = (min_brightness + max_brightness) / 2;
else if ((key == button_left) && (key == old_key))
cur_brightness -= delta_brightness2;
else if ((key == button_right) && (key == old_key))
cur_brightness += delta_brightness2;
if (cur_brightness < min_brightness)
cur_brightness = min_brightness;
if (cur_brightness > max_brightness)
cur_brightness = max_brightness;
if (cur_brightness != prev_brightness)
adjust_brightness ();
}
prev_millis = millis ();
old_key = key;
}
}
Here is a LCD screen I've been thinking of that has a 20x4 screen, keypad, buzzer, sensor I/O ports, real time clock + holder for battery, and ability to mount an EEPROM for larger data collection: http://www.ebay.com/itm/221120816817?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649
You may recognize that this shield was designed by one of our regular forum members and that any required support should be readily available.
Don
floresta:
Here is a LCD screen I've been thinking of that has a 20x4 screen, keypad, buzzer, sensor I/O ports, real time clock + holder for battery, and ability to mount an EEPROM for larger data collection: http://www.ebay.com/itm/221120816817?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649
You may recognize that this shield was designed by one of our regular forum members and that any required support should be readily available.
Don
Guilty as charged. 
Very nice!
Thank you all!