SMD LED Double Dice

I fancied a quick project so the SMD LED Double Dice  was born.

The schematic is basically a cut to size Arduino Pro Mini (3.3V 8Mhz), with two banks of 7 SMD LEDs for each Dice bolted on the side, CR2032 battery holder and power switch.

SMD LED Double Dice Schematic

I have also used the ISPTouch to allow header less (and cost effective) programming of the Atmel ATmega328P.

The layout fits fairly well on a 5x5cm board with the battery holder, button, switch and LED and current limiting resistors on the top.

SMD Double LED Dice PCB Top

The bottom has the 8Mhz crystal, ATmega328P and the ISPTouch pads (with the locating holes under the CR2032 battery holder).

SMD Double LED Dice PCB Bottom


“10” boards was ordered via DirtyPCBs and 11 arrived, they all had a little scuff on the solid rectangle portion of the silk screen (which you can’t see very well in the photo) but other than that they look OK (yes I know they’re dirty and cheap).

SMD LED Double Dice

I assembled 9 of the SMD LED Double Dice PCB which should be enough for now :).

SMD LED Double Dice

I’m currently designing a 3d printed half case for the bottom to protect the crystal etc. – this will be added to the project files below once it’s ready.

See them in action running “LED Roll Test LED flicker”.


I’ve just been programming them with AVRDude from an Arduino installation and a USBtinyISP.

To set the fuses which is only needed the first time you program a bare ATmega328p (your paths etc will most likely be different to mine).

> X:\Applications\Arduino\hardware\tools\avr\bin\avrdude -CX:\Applications\Arduino\hardware\tools\avr\etc\avrdude.conf avrdude -v -v -v -v -patmega328p -cusbtiny -e -Ulock:w:0x3F:m -Uefuse:w:0x05:m -Uhfuse:w:0xDA:m -Ulfuse:w:0xFF:m

And to upload the firmware (hex file created from within the Arduino software).

> X:\Applications\Arduino\hardware\tools\avr\bin\avrdude -CX:\Applications\Arduino\hardware\tools\avr\etc\avrdude.conf avrdude -patmega328p  -cusbtiny -F -u -Uflash:w:LED_Dice.cpp.hex

Project Files:
Schematic (png / Eagle to follow)
PCB (png top / png bottom / Eagle to follow)
Firmware (the files in bold are probably of most use):
– LED Tester (txt / hex) Turns on individual LED sections one at a time to test they’re all working as they should.
– LED Roll Test LED flicker (txt / hex) Rolls the dice and then pauses a couple of seconds and rolls again.
– LED Roll Test NO flicker (txt / hex) Rolls the dice and then pauses a couple of seconds and rolls again.
LED Dice LED flicker (txt / hex)
LED Dice NO flicker (txt / hex)

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