Word Clock

Arduino Compatible Clock Controller PCB

Construction NotesV3

A fun clock to build

Doug JacksonVK1ZDJ

Dec 2011

Licence

The Word Clock Design, PCB layout, Manual, and Firmware is Copyright 2010, 2011, by Douglas Jackson, VK1ZDJ.

This Design, PCB layout, Manual and Firmware is licenced under the TAPR Open Hardware Licence (Non-Commercial). www.tapr.org/NCL.

Permission is granted for anybody to:

• Modify the documentation and make products based upon it, provided you do not make more than ten units in any twelve month period.

• Use the products for any legal purpose without limitation. • Distribute unmodified documentation, but you must include the complete package

as you received it. • Distribute only on a non-profit basis, charging no more than the actual cost of parts,

assembly, and shipping. • Distribute products you make to third parties, if you either include the

documentation on which the product is based, or make it available without charge for at least three years to anyone who requests it.

• Distribute modified documentation or products based on it, if you license your modifications under the OHL.

Welcome

Thanks for deciding to make this great little clock project. You will find that this simple clock will be a centre piece for many discussions into the future, as well as providing a great way to tell the time. The new V3 board incorporates a DS1302 timekeeping chip, that ensures that you will experience amazing accuracy with this clock.

Because there are so many ways to construct the clock, I have broken assembly down into various documents – this document details the construction of the Arduino Controller board.

You will find that construction of this clock is very simple. If you are methodical with your construction practices, and careful with you soldering, you will find that the clock almost assembles itself.

This manual is suitable for all versions of the v3 PCB (v3a, v3b & v3c).

Arduino Controller Parts List

The first thing you need to do is to verify that you have all of the necessary components required to assemble your clock. Here is the complete parts list. Feel free to check off each component as you verify it is present.

Capacitors

10uF 1 18pF 2

100uF 1 0.1uF 2

Resistors

270R 2 10k 1

Semiconductors

AtMega168/328 micro

1 ULN2803A IC 3

CD4094 IC 3 DS1302 IC 1RED LED 1 GREEN LED 11N4001diode

1 32768Khz Crystal

1

16 Mhz crystal

1 78L05 Regulator

1

Hardware

2 Pin PCB screw connector

2 3 Pin PCB screw connector

1

5 pin 0.1 inch pin array 1 6 pin 0.1 inch pin array

1

26 pin 0.1 inch headder

1 Pushbutton 1

14 pin IC Socket 2 16 Pin IC Socket 3

18 Pin IC Socket 3 8 Pin IC Socket 1

26 Way Ribbon Cable with IDC connector

Component Layout

Use the following diagram to assist you in locating components on the Arduino Compatible Wordclock Controller PCB:

Schematic Diagram

Construction

Assembling the controller board is fairly simple. Start by inserting the links on the component side of the PCB. Care must be taken to ensure that no solder bridges are produced during soldering, linking adjacent tracks on the PCB.

You may find that the protective coating that has been applied to the hand made PCB (to prevent oxidation) requires additional time to allow a proper solder bond. This is normal.

The below picture shows the location of the jumper wires. I use of offcuts of component leads which have been bent using a pair of needle nose pliers for jumpers. There is no need to use insulated wire.

Continue assembly by inserting the IC Sockets, resistors, and 1N4004 diode. Be careful to with the orientation of the IC sockets. Pin one is indicated with a square pin on the PCB. The photo below shows 2 4 pin socket strips being used in place of the 8 pin socket – your kit should have an 8 pin socket. (I didn't have one available for the prototype).

The next step is to insert and solder the rest of the resistors, capacitors, 78L05 voltage regulator and crystals in place. Again, be careful that the correct orientation is used for the electrolytic capacitors and diode. The following photo will help..

Continue assembly by installing the LEDs, 5 pin header, 6 pin header, 26 pin header and the 2 and 3 terminal connector blocks. The LEDs must be installed so that the short lead (cathode) is located at the bottom of the board (in the square hole)

Finally, insert the IC packages. Be very carefull that the Ics are oriented so that pin one is in the correct location (matching the square hole on the PCB).

That completes assembly!

TestingThe board is able to be tested by connecting a 9V DC supply to the power input (Top Left 2 pin wire header).As soon as power is applied, the power LED should illuminate. If it does not, verify that the supply polarity is correct, and that the 78L05 has been installed correctly. There should be +9V on the input of the 78L05, and +5V on the output.After the bootloader stops, and the self test is completed (within 15 seconds), the Pulse LED should pulse at a rate of one pulse per second.You can now remove power, and connect your completed LED display PCB to the controller using the 26 way ribbon cable, and your clock should start operating.

Time set inputThe 3 pin wire connector on the board is designed to be connected to two normally open push buttons for setting the time. The centre pin is common, and the outside pins are to be connected to each time set pushbutton. One time set button increments the time, and the other decrements the time.

Minute LEDsThe 5 pin header is used for connecting a set of LEDs to allow minutes to be displayed. Simply connect LEDs, in seried with a 270 ohm resistor between each LED output, and ground. No software changes are necessary – the Version 3 software supports minutes.

The table below shows the pin connections for the optional minute LEDs.

1 GND 2 LED 1 Anode

3 LED 2 Anode 4 LED 3 Anode

5 LED 4 Anode

Programming

The Arduino compatable controller board is designed to be programmed using a FTDI USB-TTL programming cable (available from evilmadscience.com) http://evilmadscience.com/partsmenu/130-usbttlThe board is fully arduino compatable, and is able to be programmed from the Arduino IDE.Source code is available from the instructables.com project website.You need to solder a 26 way ribon cable onto the appropriate LEDs in your display. Simply strip and tin the cable into the 26 individual wires, and solder the relevant wire into the LED, as per the following diagrams:

Arduino Display connector pinout:

Pin Function1 PAST 2 TO3 Hour Seven (SEVN) 4 Minute Thirty (HALF)5 Hour Two (TWO) 6 Minute Twenty (TWTY)7 O'Clock (OCLK) 8 Minute Ten (MTEN)9 LED Common Anode (V+) 10 ITIS11 Not Used 12 Minutes (MINS)13 Hour Six (SIX) 14 Hour Three (THREE)15 Hour One (ONE) 16 Hour Eleven (ELVN)17 Hour Twelve (TWLV) 18 Extra Word 1 (DOUG)19 Minute Quarter (QTR) 20 Extra Word 2 (ARDU)21 Hour Five (HFVE) 22 Hour Four (FOUR)23 Hour Ten (HTEN) 24 Minute Five (FIVE)25 Hour Eight (EGHT) 26 Hour Nine (NINE)

Here is a picture of a sample display showing one possible wiring method.

There you go – A completed Arduino controller – I hope you have as much fun building it, as I had designing it.

Doug