How to build C3Jr, a sophisticated word clock

Like the handful of other word clocks you may have seen, all inspired from the original QlockTWO , C3Jr shows the time in words.

What makes it stand out among the DIY word clocks is, beside the professional look, its engineering: its dabble-free approach requires no more drilling holes for the LEDs, no more scissor-cutting cardboard to separate blocks of letters, no more soldering cables and terminals in the air.

C3Jr comes as a kit that includes a large PCB, electronic components, a set of high intensity diffused LEDs and mechanical parts (back and front plates, baffles etc). This kit is the result of countless hours of design, engineering, prototyping and programming by the talented Wyolum team (which also brought you ClockTHREE , the only multi-color word clock).

This instructable shows how to assemble the C3Jr kit. You will end up with a beautiful and solid word clock, as shown in the photo below.

Here are a few characteristics and "specs":
- Arduino (ATmega328) compatible, hackable/programmable using the Arduino IDE;
- open source hardware and software;
- uses the extremely accurate, temperature compensated, DS3231 real time clock chip, with backup battery;
- features a matrix of 16 x 8, individually addressable LEDs, which also allows the display of patterns/bitmaps/digits/scrolling text;
- current functionality also includes alarm (with the on-board buzzer), time and date setting from buttons;
- at 25cm x 25 cm, big enough to hang on a wall, yet small enough to stand on a desk.

The C3Jr kit can be purchased here .

Step 1 Tips. Before you start...

... soldering, browse through this list of tips:

1. Read through and understand the entire set of instructions before you get started. I know, they always say that, but heed the advice this time. It could save you hours of rework and much consternation. We've captured all of the mistakes and blunders made in creating and building the prototypes and tried to foresee problems you may have.

2. Take your time. Enjoy the build process and take a break when you feel fatigued. You will have this clock for years to come (and hand it down to your grandchildren!) so there are no worries if it takes you an extra day or week to build it.

3. Leave the paper on the front cover and front frame until final assembly. This protects the parts from scratching and smudging.

4. On soldering:

- We assume that this is NOT your first soldering project . If it is, we'd suggest getting a cheap learn-to-solder kit to get started. If this is your first project in a while, here is a quick refresher on soldering. Double and triple check that the part is in the correct place with the correct orientation (where applicable). While de-soldering is possible, it is troublesome and time consuming and risky. Make it a goal that you will not have to de-solder in the course of making this clock.

- After each step, evaluate the solder joints from the front and back of the board. On the back, the solder should be shiny and make a volcano shape, as opposed to a dome shape. On the front, you should see that the solder came all the way trough the board. If it doesn't look good, try re-heating the joint until the plated-through-hole sucks up the solder.

- Check (I use a magnifier glass) that the solder does not short neighboring parts.

- If you do make a mistake, don't panic. Use a solder sucker or, even better (cleaner, easier), de-soldering braid , to remove the solder and pull the piece gingerly while applying heat. Try not to damage traces in the process, otherwise you will need to replace them with wires (a bit ugly, but still functional).


The following parts are not provided (they are not required):
---------------------------------------------------------------------------------------
C7 - 100nF RESET Capacitor
C11, C12 - 22nF (not used if X1 is a resonator, USED if X1 is a Crystal)
CD3 - 4 pin male header
J1, J2, J3 - Use any ONE of these three locations for Power In connector (USB-b)
P1 - 8 pin male header for 7 seg. display
P12 - V_OUT
P13 - ISP
P41 - STACK-L
P42 - STACK-R
rowBoB1 - 16 bit row driver
-----------------------------------------------------------------------------------------

The schematic and board files are available here.

Comments

[Kiteman]

In step ten, if somebody is making their own version of this,it would be good if you could include (or link directly to) the Arduino code.

[florinc]

You are right. The Arduino code will be published in the next few days, here:
http://code.google.com/p/clockthree/source/browse/#svn%2Ftrunk%2Flibraries

And there is more for those who want to make their own version, I should write another step specifically for that. The circuitry, including the LED matrix, can be easily made on prototyping PCB. In fact, this is how we started, see the attached image:
- the LEDs are spaced vertically and horizontally at multiple of 0.1";
- the baffles were made out of female headers;
- the board fits into the Ribba frame from Ikea.

[WyoJustin]

FlorinC, actually the code is already there. It is the same code base as ClockTHREE. Right now there are two steps to specify the "Jr" version:

1. uncomment line 55 in ClockTHREE.h
#define CLOCKTHREEJR // uncomment this line for ClockTHREEjr

2. in ClockTHREE_02.pde use the EnglishJr faceplate
make sure that "#include english.h" and "#include german.h" are commented out.
uncomment line #34
#include "english_jr.h"

3. Around line 293 of the pde file only instantiate the englishjr faceplate:
comment out the other two (english and german)
EnglishJr faceplate = EnglishJr();


This will be made simpler in the next version.

[WyoJustin]

I take it back. For now I will leave it as a three step process. I could not find a simple way to make this into a one stepper.
Justin

[florinc]

Thanks Justin, that's a great addition.

[WyoJustin]

There are 3 kinds of people: those who know can count and those who can't.