Table Of Contents
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’ll stick 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 LED 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.
LED 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 LED 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.”
LED DICE - PARTS LIST
- 3 - 100R
- 1 - 220R
- 1 - 47k
- 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 CR2032
- Fine tinned copper wire - 30cm
- Fine enamelled wire - 30cm
- Fine solder - 30cm
- 1 - Matrix Board 11 x 12 hole
[Buy a kit](mailto:colin@elechelp.com?Subject=Buying LED Dice $10.00 plus $6.50 postage&Body=Please send details of how to pay for LED Dice $10.00 posted%20by%20air%20mail%20to%20my%20country:**___**** My%20name%20is:____) (LED Dice)**
Here are the files you will need to burn the program into the PIC12F629 micro:
;*************************************************************
;;**LED 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
;oscillator calibration
call 03FFh
movwf OSCCAL
end
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