Author Topic: Mucking about with an Arduino  (Read 3184 times)

Offline AdeV

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Mucking about with an Arduino
« on: January 02, 2014, 09:21:22 PM »
(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
Cheers!
Ade.
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Location: Wallasey, Merseyside. A long way from anywhere.
Or: Zhengzhou, China. An even longer way from anywhere...
Skype: adev73

Offline Dawai

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Re: Mucking about with an Arduino
« Reply #1 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

 

I Hung a 24 foot Ibeam this morning in the ceiling by myself, programmed a Arduino this afternoon for a solar project, Helped a buddy out with a electrical motor connection issue on the phone, then cut up a chicken for Hotwings. I'd say it has been a "blessed day" for myself and all those around me.

Offline AdeV

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Re: Mucking about with an Arduino
« Reply #2 on: January 03, 2014, 06:38:16 AM »
What no code??  Come on, share, I learn from everyone I get to see how they do things??

David

Apologies, it was pushing on for 3am & I needed to get some sleep in.... I'll publish the code tonight.
Cheers!
Ade.
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Location: Wallasey, Merseyside. A long way from anywhere.
Or: Zhengzhou, China. An even longer way from anywhere...
Skype: adev73

Offline Dawai

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Re: Mucking about with an Arduino
« Reply #3 on: January 03, 2014, 06:54:43 AM »
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.
I Hung a 24 foot Ibeam this morning in the ceiling by myself, programmed a Arduino this afternoon for a solar project, Helped a buddy out with a electrical motor connection issue on the phone, then cut up a chicken for Hotwings. I'd say it has been a "blessed day" for myself and all those around me.

Offline AdeV

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Re: Mucking about with an Arduino
« Reply #4 on: January 03, 2014, 08:56:05 AM »
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: [Select]
/*
--------------------------------------------------------------------------------
-- 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;
  }

}
Cheers!
Ade.
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Location: Wallasey, Merseyside. A long way from anywhere.
Or: Zhengzhou, China. An even longer way from anywhere...
Skype: adev73

Offline awemawson

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Re: Mucking about with an Arduino
« Reply #5 on: January 03, 2014, 08:58:40 AM »
Nicely self documented code Ade - takes me back to when I was writing 8080 & Z80 assembler code by the ream  :wave:

Andrew
Andrew Mawson
East Sussex

Offline AdeV

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Re: Mucking about with an Arduino
« Reply #6 on: January 03, 2014, 09:28:13 AM »
Nicely self documented code Ade - takes me back to when I was writing 8080 & Z80 assembler code by the ream  :wave:

Thanks, I have to do it  - my memory has always been poor, and is getting worse, so give it 2 weeks I'll have forgotten how to do this stuff. The commentary brings it all back...

Actually, I'm not sure the "how it works" block is that accurate... trying to work out if I want lsb or msb first, the digit order, etc.... every chance all that stuff is utterly wrong...

Cheers!
Ade.
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Location: Wallasey, Merseyside. A long way from anywhere.
Or: Zhengzhou, China. An even longer way from anywhere...
Skype: adev73