Arduino LCD CPU RAM Monitor

Abhishek Ghosh

By Abhishek Ghosh July 5, 2018 1:36 pm Updated on July 5, 2018

Arduino LCD CPU RAM Monitor

This is an interesting basic project which probably has some practical application in case you are going to use a custom cabinet for assembled desktop. Here is How To Create An Arduino LCD CPU RAM Monitor So That The Values Can Be Seen With USB Connection Without Need of Looking Via GUI. We need a Python script which will gather data and send to a connected Arduino board which upon receiving data will displays it on a 16×2 LCD display. We are following content from a GitHub repo :

https://github.com/djbarker/cpu-status-display

1	https://github.com/djbarker/cpu-status-display

There are many variations of such projects available all over the internet. Understanding basic is important. We can blink a LED connected to computer via command line.

Code For Arduino LCD CPU RAM Monitor

Here is the Python code for Windows :

import os
import serial
import time
import datetime
import wmi
import pythoncom
import win32serviceutil
import win32service
import win32event
import servicemanager
import socket

class AppServerSvc(win32serviceutil.ServiceFramework):
    _svc_name_ = 'LCDStatus'
    _svc_display_name_ = 'Arduino LCD Status'

    stop_flag = False

    def __init__(self,args):
        win32serviceutil.ServiceFramework.__init__(self,args)
        self.hWaitStop = win32event.CreateEvent(None,0,0,None)
        socket.setdefaulttimeout(60)

    def SvcStop(self):
        self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING)
        win32event.SetEvent(self.hWaitStop)
        self.stop_flag = True

    def SvcDoRun(self):
        servicemanager.LogMsg(servicemanager.EVENTLOG_INFORMATION_TYPE,
                              servicemanager.PYS_SERVICE_STARTED,
                              (self._svc_name_,''))
        self.main()

    def main(self):
        try:
            w = wmi.WMI()
            com = serial.Serial('COM3', baudrate=9600, timeout=1)
            time.sleep(2.5) # allows time for the serial connection to establish
            
            com.write("\nTIf a line is longer than 16 characters it will scroll to display itself.".encode())

            while True:

                if self.stop_flag:
                    break

                c = w.Win32_OperatingSystem()[0]
                m = c.wmi_property('FreePhysicalMemory')
                mem = float(m.value)/2**10 # convert to MB

                c = w.CIM_Processor()[0]
                m = c.wmi_property('CurrentClockSpeed')
                cpu_clock = int(m.value) # Mhz

                c = w.Win32_Processor()[0]
                m = c.wmi_property('LoadPercentage')
                cpu_load = m.value

                now = datetime.datetime.now()
                tstr = now.strftime("%H:%M")

                if cpu_load!=None:
                    com.write((("\nTCPU %02d%%  %04dMHz")%(cpu_load,cpu_clock)).encode())
                    
                string = ("\nBMEM %4.0fMB "%mem)+tstr
                com.write(string.encode())
                
                time.sleep(0.25)
                
        finally:
            com.write("\nBClosing serial connection.".encode())
            com.close()
            self.ReportServiceStatus(win32service.SERVICE_STOPPED)
    # end main

if __name__ == '__main__':
    win32serviceutil.HandleCommandLine(AppServerSvc)

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import os

import serial

import time

import datetime

import wmi

import pythoncom

import win32serviceutil

import win32service

import win32event

import servicemanager

import socket

class AppServerSvc(win32serviceutil.ServiceFramework):

_svc_name_ = 'LCDStatus'

_svc_display_name_ = 'Arduino LCD Status'

stop_flag = False

def __init__(self,args):

win32serviceutil.ServiceFramework.__init__(self,args)

self.hWaitStop = win32event.CreateEvent(None,0,0,None)

socket.setdefaulttimeout(60)

def SvcStop(self):

self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING)

win32event.SetEvent(self.hWaitStop)

self.stop_flag = True

def SvcDoRun(self):

servicemanager.LogMsg(servicemanager.EVENTLOG_INFORMATION_TYPE,

servicemanager.PYS_SERVICE_STARTED,

(self._svc_name_,''))

self.main()

def main(self):

try:

w = wmi.WMI()

com = serial.Serial('COM3', baudrate=9600, timeout=1)

time.sleep(2.5) # allows time for the serial connection to establish

com.write("\nTIf a line is longer than 16 characters it will scroll to display itself.".encode())

while True:

if self.stop_flag:

break

c = w.Win32_OperatingSystem()[0]

m = c.wmi_property('FreePhysicalMemory')

mem = float(m.value)/2**10 # convert to MB

c = w.CIM_Processor()[0]

m = c.wmi_property('CurrentClockSpeed')

cpu_clock = int(m.value) # Mhz

c = w.Win32_Processor()[0]

m = c.wmi_property('LoadPercentage')

cpu_load = m.value

now = datetime.datetime.now()

tstr = now.strftime("%H:%M")

if cpu_load!=None:

com.write((("\nTCPU %02d%% %04dMHz")%(cpu_load,cpu_clock)).encode())

string = ("\nBMEM %4.0fMB "%mem)+tstr

com.write(string.encode())

time.sleep(0.25)

finally:

com.write("\nBClosing serial connection.".encode())

com.close()

self.ReportServiceStatus(win32service.SERVICE_STOPPED)

# end main

if __name__ == '__main__':

win32serviceutil.HandleCommandLine(AppServerSvc)

Make sure you’re running the program as administrator, otherwise it will fail or give error codes when trying to test/run/execute your code. Here is code for Arduino, notice that LCD is using Pin 2 to 7 :

#include <LiquidCrystal.h>

/*
 * Parameters
 */
#define MAX_LEN 250 // maximum line length
unsigned long timeout = 60; // seconds
unsigned long refresh = 50; // milliseconds
unsigned long scroll = 400; // milliseconds

/*
 * Variables
 */
LiquidCrystal lcd(7, 6, 5, 4, 3, 2);

char line1[MAX_LEN];
char line2[MAX_LEN];
short pos1=0, pos2=0;
short len1=0, len2=0;
short active_line = 1;

unsigned long last_available = 0;
unsigned long last_refresh = 0;
unsigned long last_scroll = 0;
bool had_data = true;

/* Periodic memory copy function with padding.
 * 
 * dest - destination pointer
 * source - source pointer
 * pos - where to start copying from in source
 * num - number of data to copy from source to dest
 * len - the length of the source array
 * padding - what to pad with at the end
 * pad_length - how much to pad at the end
 */
void memcpyp(char* dest, char* source, unsigned int num, unsigned int pos, unsigned int len, char padding, unsigned char pad_len)
{
  if(pos+num<len)
  {
    memcpy(dest,source+pos,num);
  }
  else
  {
    int copied = 0;
    for(int i=0;i<num;++i)
    {
      if(pos+i<len)
      {
        dest[i] = source[pos+i];
      }
      else if(i<(len-pos)+pad_len)
      {
        dest[i] = padding;
      }
      else
      {
        dest[i] = source[copied];
        copied++;
      }
    }
  }
}

void setup()
{
  Serial.begin(9600); 
  lcd.begin(16, 2);
  lcd.clear();  
  for(int i=0;i<MAX_LEN;++i) line1[i] = line2[i] = ' ';
}

void loop()
{ 
  if(Serial.available()>0)
  {  
    last_available = millis();
    had_data = true;
    
    /* Read any available data. */
    while(Serial.available()>0)
    {  
      int ch = Serial.read();
      
      if(ch=='\r' || ch=='\t')
      {
        /* Ignore carriage returns and tabs. */
        continue;
      }
      else if(ch=='\n')
      {        
        delay(10); // allow serial buffer to catch up
        
        /* which line to update? */
        ch = Serial.read();
        
        switch(ch)
        {
        case (int)'T': // top line
          active_line = 1;
          memset(line1,' ',MAX_LEN);
          pos1 = len1 = 0;
          break;
        case (int)'B': // bottom line
          active_line = 2;
          memset(line2,' ',MAX_LEN);
          pos2 = len2 = 0;
          break;
        case (int)'D': // move top line down
          memcpy(line2,line1,MAX_LEN);
          pos2 = pos1;
          len2 = len1;
          active_line = 1;
          memset(line1,' ',MAX_LEN);
          pos1 = len1 = 0;
          break;
        default: // move bottom line up
          memcpy(line1,line2,MAX_LEN);
          pos1 = pos2;
          len1 = len2;
          active_line = 2;
          memset(line2,' ',MAX_LEN);
          pos2 = len2 = 0;
        }
      }
      else
      {
        /* Store new characters in the active line if there is space. */
        if(len1<MAX_LEN-1 && active_line==1)
        {
          line1[len1] = (char)ch;
          len1++;
        }
        else if(len2<MAX_LEN-1 && active_line==2)
        {
          line2[len2] = (char)ch;
          len2++;
        }
      }
    }
  }
  
  /* If enough time has elapsed and we have received some data refresh. */
  if((millis()-last_refresh)>=refresh && had_data)
  {
    char tmp[17];
    tmp[16] = '\0'; // zero terminate
    
    if(len1<=16) memcpy(tmp,line1,16);
    else         memcpyp(tmp,line1,16,pos1,len1,' ',4);
     
    lcd.setCursor(0,0);
    lcd.print(tmp);
    
    if(len2<=16) memcpy(tmp,line2,16);
    else         memcpyp(tmp,line2,16,pos2,len2,' ',4);
    
    lcd.setCursor(0,1);
    lcd.print(tmp);
    
    last_refresh = millis();
  }
  
  /* If enough time has elapsed scroll any long lines along by one character. */
  if((millis()-last_scroll)>=scroll && had_data)
  {
    if(len1>16) pos1 = (pos1+1)%(len1+4);
    if(len2>16) pos2 = (pos2+1)%(len2+4);
    
    last_scroll = millis();
  }

  /* If we haven't received any data for a while display the timeout message. */
  if((millis()-last_available)>=timeout*1000 && had_data)
  {
    lcd.setCursor(0,0);
    lcd.print("--- Awaiting ---");
    lcd.setCursor(0,1);
    lcd.print("--- data ... ---");
    had_data = false;
  }
}

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#include <LiquidCrystal.h>

/*

* Parameters

*/

#define MAX_LEN 250 // maximum line length

unsigned long timeout = 60; // seconds

unsigned long refresh = 50; // milliseconds

unsigned long scroll = 400; // milliseconds

/*

* Variables

*/

LiquidCrystal lcd(7, 6, 5, 4, 3, 2);

char line1[MAX_LEN];

char line2[MAX_LEN];

short pos1=0, pos2=0;

short len1=0, len2=0;

short active_line = 1;

unsigned long last_available = 0;

unsigned long last_refresh = 0;

unsigned long last_scroll = 0;

bool had_data = true;

/* Periodic memory copy function with padding.

*

* dest - destination pointer

* source - source pointer

* pos - where to start copying from in source

* num - number of data to copy from source to dest

* len - the length of the source array

* padding - what to pad with at the end

* pad_length - how much to pad at the end

*/

void memcpyp(char* dest, char* source, unsigned int num, unsigned int pos, unsigned int len, char padding, unsigned char pad_len)

{

if(pos+num<len)

{

memcpy(dest,source+pos,num);

}

else

{

int copied = 0;

for(int i=0;i<num;++i)

{

if(pos+i<len)

{

dest[i] = source[pos+i];

}

else if(i<(len-pos)+pad_len)

{

dest[i] = padding;

}

else

{

dest[i] = source[copied];

copied++;

}

void setup()

{

Serial.begin(9600);

lcd.begin(16, 2);

lcd.clear();

for(int i=0;i<MAX_LEN;++i) line1[i] = line2[i] = ' ';

}

void loop()

{

if(Serial.available()>0)

{

last_available = millis();

had_data = true;

/* Read any available data. */

while(Serial.available()>0)

{

int ch = Serial.read();

if(ch=='\r' || ch=='\t')

{

/* Ignore carriage returns and tabs. */

continue;

}

else if(ch=='\n')

{

delay(10); // allow serial buffer to catch up

/* which line to update? */

ch = Serial.read();

switch(ch)

{

case (int)'T': // top line

active_line = 1;

memset(line1,' ',MAX_LEN);

pos1 = len1 = 0;

break;

case (int)'B': // bottom line

active_line = 2;

memset(line2,' ',MAX_LEN);

pos2 = len2 = 0;

break;

case (int)'D': // move top line down

memcpy(line2,line1,MAX_LEN);

pos2 = pos1;

len2 = len1;

active_line = 1;

memset(line1,' ',MAX_LEN);

pos1 = len1 = 0;

break;

default: // move bottom line up

memcpy(line1,line2,MAX_LEN);

pos1 = pos2;

len1 = len2;

active_line = 2;

memset(line2,' ',MAX_LEN);

pos2 = len2 = 0;

}

else

{

/* Store new characters in the active line if there is space. */

if(len1<MAX_LEN-1 && active_line==1)

{

line1[len1] = (char)ch;

len1++;

}

else if(len2<MAX_LEN-1 && active_line==2)

{

line2[len2] = (char)ch;

len2++;

}

/* If enough time has elapsed and we have received some data refresh. */

if((millis()-last_refresh)>=refresh && had_data)

{

char tmp[17];

tmp[16] = '\0'; // zero terminate

if(len1<=16) memcpy(tmp,line1,16);

else memcpyp(tmp,line1,16,pos1,len1,' ',4);

lcd.setCursor(0,0);

lcd.print(tmp);

if(len2<=16) memcpy(tmp,line2,16);

else memcpyp(tmp,line2,16,pos2,len2,' ',4);

lcd.setCursor(0,1);

lcd.print(tmp);

last_refresh = millis();

}

/* If enough time has elapsed scroll any long lines along by one character. */

if((millis()-last_scroll)>=scroll && had_data)

{

if(len1>16) pos1 = (pos1+1)%(len1+4);

if(len2>16) pos2 = (pos2+1)%(len2+4);

last_scroll = millis();

}

/* If we haven't received any data for a while display the timeout message. */

if((millis()-last_available)>=timeout*1000 && had_data)

{

lcd.setCursor(0,0);

lcd.print("--- Awaiting ---");

lcd.setCursor(0,1);

lcd.print("--- data ... ---");

had_data = false;

}

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