Complete kit $8.50 plus $4.00 postage
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This project uses an 8-pin microcontroller to produce a tumbling dice via red LEDs.
There are lots of DICE projects on the web and many of them are copies of our original LED Dice with slowdown.
The circuit and layout has been copied by many websites and it is pleasing to know that thousands of hobbyists have built our circuit and enjoyed its features.
We now show how the same effect can be produced with a microcontroller and a few resistors. The circuit is simpler, the board is smaller and the project costs less than the original design.
That’s the advantage of the microcontroller.
This project is parts of a course where we show how to design around a microcontroller because this is the way of the future.
Once you collect the equipment necessary to burn the microcontroller, and set-up your computer with NotePad2, to write the programs you will have 2 separate areas in your work-room.
One area will consists of a soldering iron, components and experimenter boards, where you design and develop the project. The other area will consist of a computer with NotePad2, where you write the program using mnemonics (short sentences) and compile it with MPASM to produce a .asm file as well as a .hex file.
The .hex file will then be used by WinPIC to burn the micro (program the micro).
Take the micro from the programming socket on PIC Programmer MkIV, insert it into the project and view the results.
This is just like designing and producing your own chip.

Here are some of the Dice projects and kits on the web:

The Spikenzielabs project does not have a “rolling effect.”
The piezo under the board is tapped to change the LEDs. It is a $20.00 soldering project.
The .asm program is very messy

This $13.00 LED Dice from lightinthebox.com is already built and does not teach any electronics.

Another LED Dice project but no program provided

This project uses the same chip as our project but the PICAXE 08M chip is already programmed with routines and costs more than $5.00 You select the routines from a list to create a program but you are not “PIC programming.”

A Velleman kit. They are trying to sell old technology!! Note the “windowed” PIC chip!!!!!

This kits costs about $18.00 but the microcontroller is unknown.

A LED Dice project constructed on Matrix Board. Only the .hex file is provided.

This project uses ATTiny-13 micro. The PC board should have current-limiting resistors. The display does not have a “rolling Dice” effect.

Another ATTiny-13 micro LED Dice project A nice layout showing how to add surface-mount components.

This is the front page from a Silicon Chip project but the remainder of the article cannot be located.

None of the Dice projects on the web teach how to create a program and they are simply soldering exercises.
Ours is an EDUCATIONAL PROJECT.
We explain every instruction in the program so you can use them in the next project you are developing.

Here’s an interesting comment from Doug Jackson, writing for Silicon Chip:

Let’s settle an argument before it starts. Die or Dice? Sure, the Oxford Dictionary would have us say one die, two dice. But every man and his dog uses the word “dice” for both singular and plural. So we’llstick with dice.

Using a PIC allows us to significantly simplify our dice circuit. Previous designs have typically used at least two ICs, four or more transistors and many resistors and capacitors.

This project an ideal way for a beginner in micros to get a grasp of the fundamentals.

The 8-pin PIC micro we are using has 6 input-output lines and one line that is INPUT-ONLY.
We will use the input line for the switch and 4 of the other lines as OUTPUTS.
Each output line can deliver 25mA. This limitation is due to the FET transistors inside the the chip. Obviously they are microscopic and 25mA is a great achievement. Many of the other microcontrollers can only deliver 20mA per drive-line.

DRIVE CURRENT

Drive Current is the current delivered to each LED to make it illuminate.
There is a very wide range of LEDs on the market, from surface-mount, to 3mm to 5mm and they range from very poor quality to bright, high-bright and super bright.
Some LEDs require 20mA to produce good illumination while others produce a very good output with as little as 2 to 5mA.
On top of this, different colour LEDs have a different characteristic voltage-drop across them when illuminated and all these factors have to be taken into account when determining the value of the current-limiting resistor for each output.
One output has a single LED while the other outputs have two LEDs in series.
The value of dropper resistor for the single LED can range from R for a red LED requiring 5mA, to R for an orange LED requiring 20mA.
We have selected 68R for the 2 LEDs in series to provide about 10mA and 82R for the single LED to provide about 20mA.
Look at the illumination; decide which value is most suitable and adjust the current accordingly.
Red LEDs drop about 1.7v when illuminated, orange LEDs about 2v, and green LEDs about 2.3v.
This value does not change if the LED is surface-mount or 5mm, but it does change slightly when the current is increased.

THE PIC DICE PROJECT

This project is very simple because all the features are contained in the microcontroller in the form of a program.
Instead of a two chips and a lot of surrounding timing components, as in previous LED Dice projects, we have a single chip driving the 7 LEDs and a few current limiting resistors.
You can approach this project in several different ways at different levels.
You can simply buy a kit and put it together.
Or you can buy the components from your local electronics store and burn the program into the micro using PIC Programmer MkIV project and the .hex file provided.
Or you can go further and change some of the instructions in the program to produce different “rolling effects.” For this you will need the .asm file
All these levels are available because we have provided the full program listing plus hardware and software to get you into PIC Programming at the lowest cost.
The circuit is very simple. It just consists of a micro, 7 LEDs, resistors and a “roll” switch.

PIC DICE circuit using a PIC12F629 Microcontroller

The only components that may have to be adjusted are the current-limiting resistors, to get the desired brightness. We have suggested values for super-bright red LEDs, but if you want to use other colours you may have to decease the values slightly. For white LEDs, the supply voltage will have to be increase to at least 4.5v. This modification is covered in the article on the web.
You can build this project as a soldering exercise or go further and investigate the program and change some of the instructions to produce different “rolling” effects.

The PIC Dice project constructed on Matrix Board.

The underside of the board showing the “point-to-point” wiring.

The topside of the Matrix Board and the underside wiring

When the circuit is switched on, the tactile switch is pressed and the LEDs flash to represent the rolling of the dice.
The “rolling” gradually slows and a result appears on the LEDs. After 6 seconds the LEDs go out and the switch can be pressed again for another “roll.”

Here is the PIC DICE on Printed Circuit Board:

The negative of the cell holder goes to the bottom rail

<!-- TODO FIXME: broken image -->

PIC LED Dice now comes with 10mm Jumbo RED LEDs for $2.50 extra. Ask for them when ordering. The PC board is also larger.

PIC Dice PARTS LIST

Kit: $8.50 plus $4.00 postage

• 3 - 100R surface mount
• 1 - 220R SM
• 1 - 47k SM
• 7 - 3mm high-bright red LEDs
• 1 - 8 pin IC socket
• 1 - PIC12F629 microcontroller with DICE
• 1 - tactile switch
• 1 - mini on-off slide switch
• 1 - coin cell holder
• 1 - 3v lithium coin cell CR2025
• Fine tinned copper wire - 6cm
• Fine solder – 20cm
• 1 - PIC DICE PC Board

[Buy a kit](mailto:colin@elechelp.com?Subject=Buying PIC Dice $8.50 plus $4.00 postage&Body=Please send details of how to pay for PIC Dice $8.50 plus $4.00 postage%20by%20air%20mail%20to%20my%20country:**___**** My%20name%20is:____)**

Here are the files you will need to burn the program into the PIC12F629 micro:

Dice.asm
Dice.txt
Dice.hex
Dice_hex.txt
Dice.zip

;*************************************************************
;;**PIC** **Dice.asm**  *


;7 LEDs  - slow down and stops on a random face of a dice -


    list    p=12F629
    radix   dec
    include "p12f629.inc"

    errorlevel -302 ; Dont complain about BANK 1 Registers

    __CONFIG _MCLRE_OFF & _CP_OFF & _WDT_OFF & _INTRC_OSC_NOCLKOUT

    ; globals
    ;20h        ;this is the first available file


fileA           equ             26h
fileB           equ             27h
fileC           equ             28h
fileD           equ             29h
temp1           equ             2Ah
temp2           equ             2Bh
temp3           equ             2Ch

random        equ               30h


        ;5Fh            ;this is the last available file

status            equ           03h
option_reg      equ         81h


        ; bits on GPIO

pin7              equ       0       ;GP0
pin6              equ       1       ;GP1
pin5              equ       2       ;GP2
pin4              equ       3       ;GP3 input only
pin3              equ       4       ;GP4
pin2              equ       5       ;GP5


        ;bits

rp0             equ     5       ;bit 5 of the status register


Start   org     0x00    ;program starts at location 000
      nop
      nop
      nop
      nop                 ;NOPs to get past reset vector address
      nop
      nop


SetUp   bsf     status, rp0     ;Bank 1
        movlw   b'11001000'     ;GP3 input
        movwf   TRISIO
    bcf       status, rp0       ;bank 0
        movlw   07h               ;Set up W to turn off Comparator ports
    movwf   CMCON           ;must be placed in bank 0
    clrf      GPIO              ;Clear GPIO of junk
        clrf      random
        goto      Main



            ;Delay  - slow-down
        ;This is where the random number is generated. The micro very
        ;quickly comes to Del_1 while the switch is still pressed and
        ;increases Random very quickly until the switch is released.

Del_1   movlw   01h
      movwf     fileC
      movf    temp1,0
      movwf   fileB
DelY    decfsz  fileA,1
      goto    DelY
      btfsc   GPIO,3
      goto    _AA
      incf    random,1
      movlw   07
      subwf   random,0
      btfss   03,0        ;test the Carry.
      goto    _AA         ;Carry is SET if W is less than or equal
      clrf    random
      incf    random,1
_AA decfsz  fileB,1
        goto      DelY
        decfsz  fileC,1
        goto      DelY
        retlw   00

        ;This is the final display-delay before going blank

Del_10  movlw   12h
            movwf   fileC
DelZ      decfsz    fileA,1
        goto      DelZ
        decfsz  fileB,1
        goto      DelZ
        decfsz  fileC,1
        goto      DelZ


            ;This is where the program blanks the display and makes the
        ;inputs/outputs into inputs to reduce the
        ;current during SLEEP

blank     bsf       status, rp0     ;Bank 1
        movlw   b'11111111'     ;Set GP 1,2 4 5 input
        movwf   TRISIO          ;
        movf    GPIO,0
        movlw   b'00001000'     ;must clear the GPIF flag!!
        movwf   INTCON
        bsf     IOC,3
        sleep
        nop
        bcf     status, rp0     ;bank 0
        goto    SetUp



cycle     movlw     0Ch
        movwf     temp3
        movlw     20h
        movwf     temp2
cycle1  call      face1
        incf      temp2,1
        incf      temp2,1
        incf      temp2,1
        movf      temp2,0
        movwf     temp1
        call      Del_1

        call      face2
        incf      temp2,1
        incf      temp2,1
        incf      temp2,1
        movf      temp2,0
        movwf     temp1
        call      Del_1

        call      face3
        incf      temp2,1
        incf      temp2,1
        incf      temp2,1
        movf      temp2,0
        movwf     temp1
        call      Del_1

        call      face4
        incf      temp2,1
        incf      temp2,1
        incf      temp2,1
        movf      temp2,0
        movwf     temp1
        call      Del_1

        call      face5
        incf      temp2,1
        incf      temp2,1
        incf      temp2,1
        movf      temp2,0
        movwf     temp1
        call      Del_1

        call      face6
        incf      temp2,1
        incf      temp2,1
        incf      temp2,1
        movf      temp2,0
        movwf     temp1
        call      Del_1
        decfsz  temp3,1
        goto      cycle1
        retlw     00


end1      call    face1
        movf      temp2,0
        movwf     temp1
        call      Del_1
        retlw     00

end2      call    face2
        movf      temp2,0
        movwf     temp1
        call      Del_1
        retlw     00


end3      call    face3
        movf      temp2,0
        movwf     temp1
        call      Del_1
        retlw     00

end4      call    face4
        movf      temp2,0
        movwf     temp1
        call      Del_1
        retlw     00


end5      call    face5
        movf      temp2,0
        movwf     temp1
        call      Del_1
        retlw     00



face1     movlw   b'00010000'           ;
        movwf     GPIO
        retlw   00


face2     movlw   b'00000100'           ;
        movwf     GPIO
        retlw   00


face3     movlw   b'00010100'           ;
        movwf     GPIO
        retlw   00



face4     movlw   b'00000110'           ;
        movwf     GPIO
        retlw   00


face5     movlw   b'00010110'           ;
        movwf     GPIO
        retlw   00


face6     movlw   b'00100110'           ;
        movwf     GPIO
        retlw   00



finish1 call      end1
            goto      Del_10

finish2 call      end1
        call      end2
        goto      Del_10

finish3 call      end1
        call      end2
        call      end3
        goto      Del_10

finish4 call      end1
        call      end2
        call      end3
        call      end4
        goto      Del_10

finish5 call      end1
        call      end2
        call      end3
        call      end4
        call      end5
        goto      Del_10


       ;This is where the Random number is decremented to produce the
       ;final value on the display

Main      btfsc   GPIO,3
        goto      Main
        call      cycle
Main1     decfsz    random,1
        goto      Main2
        goto      finish1
Main2     decfsz    random,1
        goto      Main3
        goto      finish2
Main3     decfsz    random,1
        goto      Main4
        goto      finish3
Main4     decfsz    random,1
        goto      Main5
        goto      finish4
Main5     decfsz    random,1
        goto      Del_10
        goto      finish5


        end