Serial LCD-Display « Jee Labs Talk

Serial LCD-Display

(12 posts) (4 voices)

Tags:

No tags yet.

jeroen
Hi, my first post on this forum. Received the starterkit last week. So no experience with the Jeenodes or the arduino toolkit (absolute newbie).

I tied the components together and my first project is to have a serial display for my "headless" domotica-server. (OpenSolaris)
Like to display some information about cpu load and status of temperature sensors (velleman).
So i started with the lcd-demo program,tweaked it a little and on the serial arduino console (rel0017) things seems fine. But...

When I cat a file to /dev/term/0, only the first word is displayed, everything after a space dissappears. Same with tip and with the tool (http://todbot.com/blog/2006/12/06/arduino-serial-c-code-to-talk-to-arduino/)
Tried it with Ubuntu and OpenSolaris. (in ubuntu the device is /dev/ttyUSB0)
Baudrate = 9600 (because that is the default in Solaris)

any ideas ? (or better solutions?)

regards

Jeroen

// sketch for an LCD connected to I2C port via MCP23008 I/O expander
// 2009-10-31 <jcw@equi4.com> http://opensource.org/licenses/mit-license.php
// modified: 2010-03-14 Jeroen Bruins Slot
// Display messages on "headless" server
// a string that starts with "" sets the cursor on the first line.
// "@" sets the cursor on the second line, and "^" clears the screen.
// backlight on during display

#include <PortsLCD.h>
#include <RF12.h> // needed to avoid a linker error :(
PortI2C myI2C (1);
LiquidCrystalI2C lcd (myI2C);

void setup()
{
lcd.begin(16, 2);
Serial.begin(9600);
// Print welcome message to LCD.
lcd.print(" line1, @ line2 ^ cls 9600 baud.");
delay(1000);
lcd.noBacklight();
}

int bufferArray[250];
int output = 0;
int i = 0;
int position = 1;

void loop()
{
int count = Serial.available();
if (Serial.available() > -1)
{
```
    delay(1000);

    lcd.noBacklight();

    for (i=0; i<count; i++)

      {

       bufferArrayi;

       output = 1;

      }

   }

 if (output != 0)

   {                                          // if new bytes have been recieved  int position = 0;

    if (bufferArray0

      {                                       // Print on first line if message begins with 

       lcd.clear();

       lcd.setCursor(0,0);

       position = 1;

      }

     else if (bufferArray0

      {                                       // Print on second line if message begins with @

       lcd.setCursor(0,1);

       position = 1;

      }

     else if (bufferArray0

      {                                       // Print on second line if message begins with @

       lcd.clear();

       lcd.setCursor(0,0);

       position = 1;

      }

     else

       {

        lcd.clear();

        lcd.setCursor(0,0);

       }

     int j;

     lcd.backlight();
     for (j = position; j < count; j++)

       {

        lcd.write(bufferArrayj;

       }

     output = 0;

     memset(bufferArray, 0, count);

     count = 0;

     delay(2000);

   }
```
}
Posted 16/03/2010 13:11:56
jcw

Sorry - don't know what's wrong here. I'd remove the delays, in case it leads to serial buffer overruns. And simplify... all the way until the bug comes out in the open. That's all I can think of right now.

Posted 17/03/2010 15:58:19
jeroen
Ok, I fixed the problem and changed the setup.

My sketch is less difficult with most of the logic on the server.
On the JeeNode there is a simplied sketch to display the required info.
(one remark the line "lcd.begin(16, 2);" does not do anything so could be removed)
Line 1 displays the server os version and after few seconds the last message from my home domotica system.
Line 2 displays Cpu load , Temperature (inside and outside) ,after that the current time.

On the server I have 3 scripts: 1 script to send the two lines to the display, and two seperated scripts to create te appropriate display line. The reason for using seperate scripts is to fill lines from different applications. (line 1 for error messages, and line two for status information)

Script 1: For sending the two lines to the display

#!/bin/sh
cat /k8055/line1.txt /k8055/line2.txt | perl -ne 'chomp;printf "%-40s", $;' > /dev/term/0

Script 2: Filling line 1

#!/bin/sh
uname -vs > /k8055/line1.txt
sleep 3
tail -1 /var/apache2/2.2/htdocs/logs/system.log | cut -c 20-36 > /k8055/line1.txt
sleep 6

And Script 3 (filling line 3 this is part of a PHP application)
<?php
$temp="Tmp:";
for (;;) {

$defile1 = fopen("/k8055/testfiles0/1.analogin","r");
$bitemp = fgets($defile1);
$bitemp = round(($bitemp101/256)-23, 1);
fclose($defile1);

$defile1 = fopen("/k8055/testfiles1/1.analogin","r");
$butemp = fgets($defile1);
$butemp = round(($butemp101/256)-23, 1);
fclose($defile1);

$lcdregel1="$temp $bitemp $butemp \n";
$update1 = fopen("/k8055/line2.txt","w");
fwrite($update1,"$lcdregel1"); // schrijf een regel
fclose($update1);
sleep (6);

$tijd="De tijd is";
datedefaulttimezoneset('Europe/Amsterdam');
$datum = date('H:i');
$lcdregel1="$tijd $datum";
$update1 = fopen("/k8055/line2.txt","w");
fwrite($update1,"$lcdregel1");
fclose($update1);
sleep (6);
$lcdregel1 = exec("/usr/bin/uptime | tail -17c ");
$update1 = fopen("/k8055/line2.txt","w");
fwrite($update1,"$lcdregel1"); // schrijf een regel
fclose($update1);
sleep(6);

}
?>

And the Jeenode sketch

#include<PortsLCD.h>
#include<RF12.h> // needed to avoid a linker error :(

PortI2C myI2C (1);
LiquidCrystalI2C lcd (myI2C);

void setup(){
// set up the LCD's number of rows and columns:
lcd.begin(16, 2);

// initialize the serial communications:
Serial.begin(9600);
}

void loop(){
// when characters arrive over the serial port...
if (Serial.available()) {
// wait a bit for the entire message to arrive
delay(100);
// clear the screen
lcd.clear();
// read all the available characters
while (Serial.available()> 0) {
```
     // display each character to the LCD

     lcd.write(Serial.read());

   }

 }
```
}
Posted 25/03/2010 18:44:30
tor

My only comment is that you now have several scripts that may try to write to the Jeenode at the same time - which would occasionally trash your messages.

I'm doing more or less the same but with one script doing the actual writing to the Arduino to avoid such problems.

Good luck!

Posted 26/03/2010 13:22:15
jeroen

There is only one script writing to the LCD. The other scripts creates the messages which are written to a memory based filesystem. I agree that it is possible, but did't see it yet.
If I have some sparetime ,I will change it. Thanks for the comment

regards

Posted 26/03/2010 19:42:09

jeroen

found a great idea in this forum (marvinGS) Use the blink plug in combination with the LCD. I used some of marvinGs's code: For me a succesfull project

    #include 
    #include 
    #include

    PortI2C myI2C (1);
    LiquidCrystalI2C lcd (myI2C);
    BlinkPlug buttons (4);
    byte light = 0;

    void setup(){
      lcd.begin(16, 2);
      Serial.begin(9600);
    }

    void loop(){
      char buf[12];
      byte pushed = buttons.pushed();
      if (pushed) {
        if (pushed & 1){                // green button = light on
          light = 1;
        }
        if (pushed & 2){                // red button = light off
          if (light == 1){
            light = 0;
          }
        }
      }
        if (light){
       lcd.backlight();                // always on
        }
      else{
        lcd.noBacklight();              // lights off  
      }

      if (Serial.available()) {         // characters arrive
        delay(100);                     // wait
        lcd.clear();                    // clear screen
        while (Serial.available()> 0) { // read characters
          lcd.write(Serial.read());     // display characters
        }

regards Jeroen

Posted 07/04/2010 16:28:21

marvings

That was the "cut down" code to dig into a problem. The real code also has a timer for temp light that is activated by pressing the red button when the light is already off OR important data. The the light stays on for 6 seconds and then switches off again...
I can put it in here if you like...

Posted 07/04/2010 20:02:24
jcw

Note that if you'd want to go real fancy, you could even implement software PWM to dim the backlight...
Oh, and one other idea: there's a spare I/O pin on the LCD plug, which could be used for a button and/or LED.

Posted 07/04/2010 20:12:07
jeroen

Hmm good idea, perhaps blink the display when inmportant messages are send to the display. Something for revision 2
regards

Posted 07/04/2010 20:41:34
marvings

Oh, i need to keep that spare I/O in mind. An extra button or light close to the LCD may be useful some time ;)

Posted 08/04/2010 14:12:24
jeroen

I included the in chip thermometer, now the server sends info to the LCD (serial) and the RF12 sends temperature back to the server.

Posted 30/04/2010 21:36:20
jeroen

I created a little document with pictures. .
(edit by jcw: added <>'s to make the URL live)

Posted 12/06/2010 19:37:27