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Topic: Voltage Time Graph - GLCD (192x64) (Read 1 time) previous topic - next topic


Hi all,
I refrain from calling this a scope on this forum because we know it isn't, but it is quite close to what an Arduino could call a scope, right?  ;)
Anyway, there is now a video on YouTube.  I am going to try to add some logging to it, but I need a new thermistor first (I might have melted the last one, hense the croc clip as a probe :P)

Anyway, here is the video:




A few comments:

1) Nice - and ugly - but nice!
2) Get a tripod...
3) Get a macro lens...
4) Get me outta here!
5) Code? Schematic? Please?

Seriously - that looks interesting, it was hard to follow what was going on with all the bouncing around, but the basics could be seen.

Something that I have thought about doing (but will probably never get around to) is using an Arduino and a GLCD to create a simple digital logic analyser; basically quickly sampling one port (6 bits) for HIGH/LOW transitions using direct port I/O in the quickest manner possible (likely using an unrolled loop), and storing the results in memory (triggered off one of the pins in the port, an internal trigger, or a different external trigger pin), then showing the results on the GLCD (scrolling, zooming, examining different pins side-by-side, allowing for a dump to the serial port, etc).

While it wouldn't be fast, for most users of the Arduino I think it could be very useful...

I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.


5) Code? Schematic? Please?

Times two.....  :)


Apr 27, 2010, 10:31 pm Last Edit: Apr 27, 2010, 10:59 pm by Gray_Malkin Reason: 1
The code has developed from when this was shot (only hours ago) - sorry about the shakey camera man, but it was the best I could do (am student therefore skint)

Code: [Select]
#include <EEPROM.h>
#include <ks0108.h>
#include "SystemFont5x72.h"  // system font
#include "ArduinoIcon.h"     // bitmap

unsigned long startMillis;
unsigned int loops = 0;
unsigned int iter = 0;
int Benchcount = 0;
int InputPin = 5;
int PlotVoltage = 0;
int VoltageValue = 0;
int DisplayFromEEPROM = 1;  // 0 = Record, 1 = Display
int EEPROMPosition = 0;     // Store the current location in memory.
int d = 1;
 int p = 0;
 int x = 0; //x graph coordinate
 int y = 0; //y graph coordinate
 int a = 0; //old x graph coordinate
 int b = 0; //old y graph coordinate

int delayTime = 1000;        // Change how often data is recorded (will change recording duration - total (MS) = 512 * delayTime)

// Get things ready
void setup(){
 GLCD.Init(NON_INVERTED);   // initialise the library, NON_INVERTED writes pixels onto a "white screen"
 GLCD.ClearScreen();        // Clear the GLCD Screen memory ready for drawing on.
 GLCD.SelectFont(new_Font); // switch to fixed width system font

void  loop(){   // run over and over again
 // TODO:
 //  o Add a physical toggle for read/record
 //  o Add more information down the right side
 //    - High
 //    - Low
 //    - Mode (playback, reccording)
 //  o Add some welcome images and even Images
 //  o Maybe add Mass storage for logging
 //  o Add another line from another pin out?
 //  o Serial out the readings
 //  o Add a pause between readings so the memory doesn't fill so quickly
 //     and more information is on the graph
 //      - Ajustable by a POT
 //      - Change the playback speed for long "exposure" graphs, so time travels faster.
 //  o Buy a Thermistor and perhaps record tempreture
 //Dotted Line to Center Plot Graph Area Horizontally
 d = 0;
 for (int i=0; i <= 63; i++){ //dotted graph line
   GLCD.SetDot(d, 32, BLACK);
   d = d + 2;

 GLCD.DrawRect(0,0,128,63, BLACK);
 static float p;
 static float x;
 // Erase Previous Information Panel Pixels
 GLCD.FillRect(129, 0, 64, 62, WHITE);
 if(DisplayFromEEPROM == 0)
   //Read input
   PlotVoltage = analogRead(InputPin);  // Each byte of EEPROM memory can hold 1 reading. So a ATMega 328 can store 512 readings.  About 3 screens full.
   if(EEPROMPosition > 511)
    EEPROMPosition = 0;
   //Record Input
   EEPROM.write(EEPROMPosition, PlotVoltage / 4);
   if(EEPROMPosition > 511)
    GLCD.Puts("End of memory, restarting");
    GLCD.Puts("To change record speed please");
    GLCD.Puts("edit the loop delay.");
    EEPROMPosition = 0;
   GLCD.PutChar(127);// 127 the address of the Play symbol in the "System" font.
   // Read Input
   PlotVoltage = EEPROM.read(EEPROMPosition) * 4;
 //Move on the EEPROM Read Location
 VoltageValue = (PlotVoltage / 2.04799979);
 int whole = VoltageValue / 100;
 int fraction = VoltageValue - whole * 100;
 // Write the progress through the memory (reading or writing)
 GLCD.GotoXY(130, 34);
 int progress =  EEPROMPosition * 0.1953125;
 GLCD.Puts("%  Prog");
 //Draw Rectangles on top and bottom corners to display RAW Data from Analog Reading
 GLCD.Puts("Bin: ");

 GLCD.GotoXY(130, 12);
 GLCD.GotoXY(158, 12);
 if (PlotVoltage > p){ //print peak graph value
    // GLCD.FillRect(97, 05, 29, 10, WHITE);
    // GLCD.GotoXY(98,119);
    // GLCD.PrintNumber(PlotVoltage);
    p = PlotVoltage;
//Add Scaling...Bottom most line (y=63 is 0V, y=1 is 5V)
GLCD.DrawLine(0, 0, 0, 63, BLACK);  //Line for Scaleing Tally Marks
GLCD.DrawLine(0, 0, 4, 0, BLACK);   //Topmost Mark
GLCD.DrawLine(0, 8, 2, 8, BLACK);
GLCD.DrawLine(0, 16, 4, 16, BLACK);
GLCD.DrawLine(0, 24, 2, 24, BLACK);
GLCD.DrawLine(0, 32, 4, 32, BLACK); //Center Mark
GLCD.DrawLine(0, 40, 2, 40, BLACK);
GLCD.DrawLine(0 ,48, 4, 48, BLACK);
GLCD.DrawLine(0, 56, 2, 56, BLACK);
GLCD.DrawLine(0, 63, 4, 63, BLACK);//BottomMost Mark

 int y = 63 - (PlotVoltage /16);   //y coordinate of graph curve  ***Careful when adjusting the '/16' part. Y should be where you want the lowest reading displayed and
 if(b == 0){                       //                            the divisor number adjusts the scaleing (sensitivity) based on where that line is...
 b = y;                            //                            The lower the number, the higher sensitivity/max reading is plotted on graph
 GLCD.DrawLine(a,b,x,y, BLACK);
 x++;                              // Add 1 to old x coordinate for line drawing in right direction
 if (x == 128){                    //clean screan when graph cycle will start again from left
 x = 0;                            //x coordinate to start graph from left again

 a = x;                           //old x coordinate to use for drawing line to new x coordinate
 b = y;                           //old y coordinate to use for drawing line to new y coordinate
 delay(delayTime);                //Make the memory "last" longer by taking readins less often

I modified the code out of a post from Metalfan1185.  I changed it to support 192x64 screen size, then I added some recording and commented it a little more.  After this you can see my todo list.  Originally the delay in the loop wasn't explicit but caused by calculation time, I have added a delay (and ajustablility) to the loop too to change the recording duration.

Data is automatically logged in the EEPROM, if you have anything important in yours I suggest you comment out the writing part should you run the program.
[edit]I may also buy an EEPROM chip standalone for the storage (as opposed to an SD card) and perhaps show elapsed time too.[/edit]

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