WordClock

Summary

The origin of an idea, jibberjabber and don't do it 3 times

The Japanese v1 version. Much more samples at the bottom!

• The main board : a board, an Arduino clone minus the USB, that can have a RTC (if possible 2 different types, choose your weapon), embeds a voltage regulator and that could drive without any external component the led board in its basic format and be extended a minimum at least.
• The led board : a 5x5 leds board that can be used as is or chained with others (vertically, horizontally) to make more detailed boards

• You just want to make a clock ? ok, use the "main board" : you already have an arduino clone and a pad for your RTC. All the pins are accessible so plug the free ones to drive your !
• You want to make a WordClock 5x5 ? Use the main and the led board, put one on top of the other: tada !
• You want to make a Binary clock ? Use the main and the led board, put one on top of the other: tada ! Just pick different led colors and change how you display the time in the in-memory table. Leave the microcode do the drawing, it knows how to.
• You want to make a 5x10 clock that shows on the left the dates on the right the time ? Solder 2 led boards together and use the main board
• ... and so on, limit is your imagination

Windmill version

Low voltage Nixie tube version ardReveil v5 Tubed

Credits and thanks

• The first inspiration (thanks for sharing) :
  • http://www.instructables.com/id/The-Word-Clock-Arduino-version/
  • Improved one http://www.instructables.com/id/The-Wordclock-Grew-Up/
• The exact stuff I wanted to do ... I have to change my project from unique to rare ... I hate that guy...
  • http://www.youtube.com/watch?v=Y5HIMbGajp0
  • http://www.youtube.com/watch?v=CJosltwJq8s
  • https://github.com/suapapa/HangulClock
  • https://picasaweb.google.com/118040095502884745897/KoreanWordClockWithArduino

Schema

Led board

Controller board

Main board v1.0 (Jan2012)

• Atmega 328 (or compatible)
• ISP pins
• Crystal and its pair of caps
• Footprint for DS3231 and DS3234
• CR2320 button battery connector (if not used short the VBAT to GND, that is what Maxim advises for its DS3231 and DS3234, don't leave floating)
• LM7805 voltage regulator
• Pinout compatible with led board with solderpad to enable
  • This means if you solder the solderpads, you can drive the leds directly through the atmega pins (5x5 pins) without any other wiring nor shift register. I should add a schema to make it clear ... 'cause it's a really good idea I think!
  • Arduino's pins 0-4 (PD0-PD4) control the rows A-E, Arduino's pins 9-5 (PB1-PB0,PD7-PD5) control the rows 1-5. And yes columns are in reverse order, no there's no specific design idea under this state of fact.

Instructions for v1.0

• Works only with DS3234
• You must solder the wire to /CS to pin 10, and on the solder pad link it to ground
• You must add a battery CR2032 otherwise it won't work
• Cap C3 is not necessary if you don't use voltage regulator

Main board v1.1 (Feb2012)

Instructions for v1.1

• Works with DS3231 (corrected footprint)
• Bug with DS3234 : the pin 19 must NOT be soldered to the pad (it will ground it), but air-wired to pin 18 of the MCU (PB4 MISO)
• You must add a battery CR2032 otherwise it won't work
• Cap C3 is not necessary if you don't use voltage regulator

Instructions for v1.2

• Works with DS3231 and DS3234 this time (!)

Code and instructions

The source

Set the fuses

avrdude -v -v -p m328p -c avrispv2 -P COM1 -U lfuse:w:0xf7:m -U hfuse:w:0xd9:m -U efuse:w:0xff:m

Upload the binary

avrispv2.name=Pololu AVRISPv2 clone
avrispv2.communication=serial
avrispv2.protocol=avrispv2

Display idea bank

The original mask	The japanese v1 言時計 mask	十一(時)三十九(分)午後 //means 11:39 PM

Pictures

The Japanese v1 '言時計' front with a Altoid for the size comparison. Board is 5x5 cm. In blue the hours, in white the minutes, pink is the "afternoon flag". Picture time was 十(時)二十五(分)午後 means 10:25 PM (hard to read on the picture took in low light)	The Japanese v1 view by the side. No comment about the ugly buttons poorly hotglued to the back, thanks. This time I forethought and hid them behind.

Links

• Another rendition of the Wordclock, with 5 minutes approx, led driver for continuous display plus nice surprises : a attiny2313 at the heart and the whole program in assembler (an art being lost). Respect sirs! http://dev.frozeneskimo.com/embedded_projects/word_clock

Captain's log

Led board

Main board

• DS3231 : (Major) I picked the wrong package, the trace is way too small, impossible to solder... I feel like an idiot... no wait, I made provision to use also a DS3234 : it works ! I feel like a genius again. Anyway, let's fix that trace since DS3231 is easily encountered chip (or DS3232?)
• /CS pin : (minor) for the DS3234 the /CS pin could be (via a solder pad) connected to one Atmega pin or to gnd. I misread the doc, it can't be always connected to ground, the change of state is meaningful.
• Led board connection pins : (minor) slight mistake in placement, they are not exactly at the right place. I would say that the right one (labelled "east") is ～1mm too high. Although I thought I checked it, seems I anyway made the mistake. It's ok since you can connected it anyway, it's just not nice, it appears to be just a little screwed. Let's fix this next time.
• RTC connections : (nice to have) seems on some schema people add pull down or caps to the RTC component. It's not mandatory, not even on the constructor datasheet, but could be a plus or at least save some space for it.