The Shop > Electronics & IC Programing

Mucking about with an Arduino

(1/2) > >>

AdeV:
(moved from Gallery, which really was the wrong place...)

No construction here (other than a spaghetti mess on the breadboard) - and the only shop tool that got used was a hacksaw to cut some perspex, and the sandblaster to "frost" it!

http://meddlingmonk.blogspot.co.uk/2014/01/cheap-4-digit-displays-from-sparkfun.html

Dawai:
What no code??  Come on, share, I learn from everyone I get to see how they do things??

David

 

AdeV:

--- Quote from: Dawai on January 02, 2014, 09:46:51 PM ---What no code??  Come on, share, I learn from everyone I get to see how they do things??

David

--- End quote ---

Apologies, it was pushing on for 3am & I needed to get some sleep in.... I'll publish the code tonight.

Dawai:
Yeah, I got my rear end spanked before my 10pm bedtime last night.. My arduino-divider head, the 10x stepper drive, 200 ppr motor ran TWO RPM.. IN all of my two weeks programming arduino's I have never...

Runs (guessing) 2,000 rpm on a pc and Mach3 software.

Looking forward to seeing the code on your project.

AdeV:
OK, here's the code. I'll post it to the blog site once I work out how to constrain it to a scrolly window...


--- Code: ---/*
--------------------------------------------------------------------------------
-- 7 Segment Dual Scrolling Display
-- by Ade Vickers
--
-- Adapted from LucidTronix 7 Segment LED and 74HC595 shift
-- register tutorial at: http://www.lucidtronix.com/tutorials/41
--
-- Circuit requirements:
--   3x 74XX595 shift registers
--   2x 4-character LED displays (common anode or cathode)
--   Current limiting resistors - 1 per segment. Use resistor arrays, much neater
--   Decoupling caps to taste
--   An Arduino.
--
-- Version  On          By  Comment
-- -------- ----------- --- ----------------------------------------------------
-- 1.00     02-Jan-2014 JAV Created
--
--------------------------------------------------------------------------------
*/

// SPI interface.
int dataPin = 2;
int latchPin = 3;
int clockPin = 4;

/*
Alphanumerics
    0 1 2 3 4 5 6 7 8 9
    a b c d e f g h i j
    k l m n o p q r s t
    u v w z y z -   _ ^

Invert all 0/1s if you are using a common cathode display
*/
byte dec_digits[] = { 0b00000011,0b10011111,0b00100101,0b00001101,0b10011001,0b01001001,0b01000001,0b00011111,0b00000001,0b00001001,
                      0b00010001, 0b11000001, 0b01100011, 0b10000101, 0b01100001, 0b01110001, 0b01000011, 0b11010001, 0b10011111, 0b10001111,
                      0b10010001, 0b11100011, 0b01010111, 0b11010101, 0b00000011, 0b00110001, 0b00011001, 0b11110101, 0b01001001, 0b11100001,
                      0b10000011, 0b10100011, 0b10101011, 0b11111111, 0b10011001, 0b11111111, 0b11111101, 0b11111111, 0b01111111, 0b11101111 };

// Position codes
byte dec_display[]= { 0b00010001, 0b00100010 ,0b01000100, 0b10001000 }; 

// The message to display. Terminates with char 255 (because it turns out zero is a valid character, doh!).
// TODO: Read from serial port?
byte message[] = {38, 36, 39, 36, 38, 37,  7, 36, 28, 14, 16, 22, 14, 23, 29, 37, 13, 18, 28, 25, 21, 10, 34, 37, 12, 24, 30, 27, 29, 14, 28, 14,
                  34, 37, 24, 15, 37, 28, 25, 10, 27, 20, 15, 30, 23, 37, 37, 37, 29, 17, 10, 23, 20, 28, 37, 16, 30, 34, 28, 37, 37, 39, 36, 38,
                  36, 39, 37, 37, 37, 255};
int msgLength;

// Loop variables
int iPos = 0;    // Position in message to start sending digits this time (assuming we're scrolling the message)
int iCount = 0;  // Counter to provide a delay


void setup() {
  //set pins to output so you can control the shift register
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
 
  // Work out how long the message is
  // Max 1000 chars.
  // Use a Geordie loop for this
  for (int yi = 0; yi <= 999; yi++) {
    if (message[yi]==255) {
        msgLength = yi;
        yi=1000;  // Quit the loop now
    }
  } 
}

void loop() {

  int _d0, _d1;  // The 2 digits we will activate
 
  // HOW IT WORKS
  // There are 3 shift registers chained together, in left-to-right order DIG1, DIG2, DIGSELECT
  // DIG1 can display any one of the 4 digits at a time. The 4 MSBits of DIGSELECT choose which one is ON.
  // DIG2 is identical. The least significant 4 bits of DIGSELECT choose which one.
  // e.g. to show the number 1 at position 1 (counting L->R), we load 3 bytes: 1001 1111, 1111 1111, 1000 0000
  // So DIG1 gets 1001 1111 (= segs b & c switched on - remember, active LOW on the cathode),
  // DIG2 gets 1111 1111 = all off
  // DIGSELECT gets 1000 0000 = display digit 1 in DIG1
  //
  // e.g. to show 1234 5678, we would:
  //  - Send 1 (1001 1111), 5 (0100 1000) and 1000 1000, pause a ms or 2, then
  //  - send 2 (0010 0101), 6 (0100 0001) and 0100 0100, pause a ms or 2.... then the next 2 digits.
  // Then repeat.
  // 
 
  for (int digitOffset = 0; digitOffset < 4; digitOffset++) {

    // Set the appropriate digits.
    _d0 = iPos + 4 + digitOffset;
    _d1 = iPos + digitOffset;

    // These 2 lines cause the message to wrap around when we run out of characters.
    if (_d0 >= msgLength) _d0 = _d0 - msgLength; 
    if (_d1 >= msgLength) _d1 = _d1 - msgLength;

    // Write the appropriate digits
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, LSBFIRST, dec_digits[message[_d0]]);
    shiftOut(dataPin, clockPin, LSBFIRST, dec_digits[message[_d1]]);
    shiftOut(dataPin, clockPin, LSBFIRST, dec_display[3 - digitOffset]);
    digitalWrite(latchPin, HIGH);

    // Wait 5ms to allow POV, then move to the next digit
    // Turns out we don't need this. Run the bugger as fast as possible, otherwise
    // it just flickers.
    //delay(2);
 
  }

  // Cheesy delay loop. After 200 counters, move to the next digit in the message.
  // Comment out to prevent scrolling. Adjust value to adjust scrolling speed.

  iCount++;
  if (iCount > 200) {
    //Shift to the next digit
    iCount = 0;
    iPos++;
    if (iPos >= msgLength) iPos = 0;
  }

}

--- End code ---

Navigation

[0] Message Index

[#] Next page