Stand for ClockTHREE

Some time ago I received, as a gift, this smart and very useful stand from fellow clock enthusiast Nicholas in San Diego. He designed it and made it specifically for ClockTHREE. Simple yet elegant, this is essential if you want your C3 on the desk or table.

I did not have the chance to appreciate it until now, with an older ClockTHREE borrowed from a friend (I gave it to him as a gift). Here is the C3 on the stand, a perfect fit!

Thank you Nicholas! Keep up the great work!

Details on assembling ClockTHREE v2

I just finished assembling another ClockTHREE v2 and I realized that there are details that need a bit of clarification (and not captured in the original building instructions). These are related to the orientation of the RGB LEDs and the battery holder for RTC. Not a lot of info, but I felt I have to record these, since I will have to go through the exercise of figuring it out again next time I assemble another C3.

Here are the pictures worth a thousand words.

First the LEDs, shown laying down in the correct orientation. The longest pin, the common node, is closer to the bottom of the PCB (where the ATmega328 is).

Because the LED pins are only 0.05" apart (as opposed to 0.1" in a normal LED, or most other components for that matter), special attention must be paid when soldering these RGB LEDs. There is a tendency of shorting two adjacent pins, so make sure that doesn't happen, by checking with a magnifying glass (or with the ohmmeter). To avoid the possible shorts, I bend the pins outwards, away from each other, as shown below.

Note: One of the advantages of C3 v2 over C3 v1 is that the RGB LEDs can be inserted directly, all the way through, without the need to use the bending tool (as shown in the tutorial for v1).

Second, the battery holder. If you use one like mine, here is how it should be placed.

Note that the board was smartly designed to allow the use of many types of battery holders, including those all-metal ones (either SMD or through-hole).

Also shown are the pull-up resistors required if you solder the DS3231 RTC chip directly to the (back of the) board (and not use the ChronoDot).

Another detail worth mentioning is that the buzzer I am currently using in Wise Clock 3/4 gives a very faint sound when used in C3/C3Jr.

C3Jr on Kickstarter

Do you want the best deal on C3Jr?
Here it is, on kickstarter.



Already exceeded the goal of $2,500, it will be a sure thing in 21 days from now. I am guessing that the Wyolum team is already busy assembling them :)

The Doomsday clock (pledge $500) looks especially interesting, made of 3 adjacent C3Jrs. Lots of possibilities with this very large display, check out the video.

ClockTHREE v2

Although ClockTHREE v2 is yet to be officially introduced by the Wyolum team, I could not resist the temptation of showing off this beautiful new board.

Compared with v1, v2 has a few new features worth mentioning:

• it can accommodate both piranha RGB LEDs and 10mm RGB LEDs (common anode);
• as real time clock, supports DS1307, DS3231 and ChronoDot and wyolum's own rtcBob;
• three kinds of different coin battery holders (for RTC backup battery) are supported;
• the power socket can be mounted in 3 different places;
• no more tweaking of the terminals is required when using the 10mm RGB LEDs.

The other great features are intact:

- relatively easy to build for such a large and complex kit, with well-written documentation, both on-line and on PCB's silkscreen;

- Arduino (ATmega328)-compatible: uses Arduino IDE for sketch upload;

- display consists of 16x10 RGB LEDs + 16x2 single-colour LEDs;
- on-board speaker/buzzer for the alarm;

- word-clock functionality, user-settable time and date etc.

An assembled ClockTHREE v2, with piranha LEDs, is shown in the photo below. 

A new baffles design is in the works.
Should be offered in the store anytime now.

Related posts:

• ClockTHREE completed

Buy complete C3Jr kit

Updated Sep 15, 2012
This kit is sold now by wyolum.

Here you can buy a complete C3Jr kit, that will make a wonderful word clock once assembled (assembly instructions here). All you need is a soldering iron and some (almost trivial) soldering skills. The kit comes with the ATmega328 processor already loaded with the latest sketch (no need for you to program it).
Please contact me if you want an assembled and tested C3Jr.

Related posts:

• Other kits offered in the store

Assembling C3Jr kit

Assembling C3Jr kit is a medium-challenge project:

• all components except the RTC chip DS3231 (which comes soldered to the board) are through-hole;
• the spot and orientation of each component are printed on the board very clearly;
• sockets are provided for each integrated circuit;
• placing and soldering the components takes a few hours;
• it is very important to pay attention to the correct orientation of the polarized components (LEDs, electrolytic capacitors, transistors, ICs), since any mistake takes time and effort to repair;
• double check every time before soldering any component, even resistors.

The C3Jr kit you received includes (as shown in the photo):

• large (18cm x 23cm) PCB;
• ATmega328 with 28-pin socket;
• 16MHz crystal + two 22pF capacitors;
• 74LS154 and 24-pin socket;
• STP08DP05 and socket;
• DS3231, pre-soldered to the board;
• CR2032 (3V) coin battery and battery holder;
• 130 diffused white (or blue, on request) 5mm LEDs;
• 17 PNP transistors 2N5401;
• 4 decoupling capacitors 100nF;
• 100uF electrolytic capacitor;
• 17 resistors 100 ohms;
• 6 resistors 10K;
• 2 resistors 4K7;
• 2 resistors 1K;
• 2 resistors 680 ohms;
• USB type B (power) connector;
• speaker/buzzer;
• 6-pin right-angle male header used as FTDI connector;
• 4 right-angle push buttons;
• 5k potentiometer;
• set of laser-cut, black plastic, baffles;
• laser-cut acrylic faceplate with your favorite choice of font;
• laser-cut plastic backplate;
• set of standoffs, screws, nuts, washers.

The step-by-step assembling instructions are presented below.

1. Place and solder the 100 ohm (brown-black-brown) resistors, 17 of them.

2. Place and solder the 6 resistors of 10K (brown-black-orange).

3. Place and solder the 2 resistors of 4K7 (yellow-purple-red), then the 2 resistors of 1K (brown-black-red), then the last 2 resistors, of 680 ohm (blue-grey-brown), as shown in the photo below.

4. Insert and solder the sockets for integrated circuits marked U3, U4 and U5. There are 3 sockets and they need to be placed with the notch matching the silkscreen markings. The photo below shows (in the upper-right corner) 2 rows of 12 machined female pins (also used as IC socket) where normally is the place for the 16-pin 0.3" socket.

If it happens to solder any of these sockets with the wrong orientation, don't try to fix anything; just make sure that the ICs are inserted with the correct orientation, matching that on the PCB's silkscreen.

5. Place and solder the decoupling capacitors (100nF), then the electrolytic capacitor (100uF), as shown in the next photo. The 100nF capacitors don't have polarity, so their orientation is not important. But the 100uF electrolytic capacitor (black small cylinder) must be positioned with the negative terminal (marked with a minus) closer to the right edge of the board.

6. Place and solder the USB type B connector (used here as power jack), in one of the 3 available spots, depending on how the clock will be displayed: J3 if on the wall or J1 if on the desk. (In the photo below, the USB connector is mounted for a desk configuration.) Then solder the 6-pin male right-angle header (used as FTDI connector) and the two 3-pin male headers. Next, solder the buzzer, the resonator (or crystal + 2 capacitors), the four right angle push buttons, the coin battery holder and finally the dimming pot. The board should look now like in the photo below.

Note that the RESET button and the debug LED are optional (and not populated on the board in the photo).

7. Solder the 17 PNP transistors, their orientation according to the silkscreen.

8. Solder the LEDs. Pay maximum attention to their orientation. The short pin is the cathode (negative terminal). The cathode is also indicated by a straighten arc at the bottom of LED's plastic capsule, see the drawing below.

When placing the LEDs, their cathode (short terminal) always goes toward the label on the silkscreen.

The board with the LEDs soldered looks as in the next photo.

There are 2 optional LEDs in addition to the 128 LEDs in the matrix: one (D260) is the power indicator and may be annoying since it is ON all the time, the other (D258) is used for debug purposes.

9. Insert the ICs into their respective sockets. Before doing this, bend all the pins on each side at once, by pushing them against the table, so both rows of pins become parallel.

Make sure the notch of each IC, indicating where the pin counting starts, matches the notch in the silkscreen (and also on the socket, if you place those correctly in Step 4).

The ATmega328 microcontroller comes programmed with the latest release of the C3Jr software. New sketches can be uploaded, with the Arduino IDE, through the FTDI cable/breakout (plugged into the 6-pin FTDI connector).

10. Assemble the enclosure, starting with the backplate/bottom plate. Insert the 4 long screws into the 4 holes closer the center of the backplate.  Secure each with a small nut as shown in the photo below.

Slide the completed PCB on the protruding screws, with the buttons near the two keyholes at the top of the backplate. Then place each of the 4 small baffle locators on every screw and secure with the 4 small nuts, as shown in the next photo.

Interlock the baffle grid into place with the angled edge against the PCB. This provides a little extra space for the components. You can start with the top and bottom vertical pieces and slide all the horizontal pieces into place. Place the whole assembly on a flat surface (cardboard, book etc) and flip over, then transfer it over LED matrix region of the PCB. You can now install the remaining vertical pieces. Next, insert the 4 screws into each corner of the backplate and secure with the 20mm standoffs. 

Note that the protection-paper on the baffles is still there. I did not bother to peel it off, but it doesn't seem to affect the functionality. After all, the purpose of the baffles is just to separate the LEDs in the matrix.

Install the faceplate on top of the baffles and secure with the 4 provided socket screws.

11. Power up the clock with the USB type-B cable, similar to those used for USB printers. (You can also use the FTDI cable to power it up, but ensure that the PWR SEL jumper is in the correct position, on the left 2 pins.)

Since the microcontroller is loaded with the latest C3Jr software, the clock will work right away (you just need to set the time.)

Related posts:

• Introducing C3Jr kit

Introducing C3Jr kit

Although I posted about ClockTHREE Junior (aka C3Jr) here, this is its formal introduction in my blog.

C3Jr is an Arduino-compatible, open-source alarm "word clock", which displays the time in words, similar to the original QlockTWO(*). It is the result of numerous hours of electronic design, mechanical engineering and programming by the Wyolum team. The goal of this effort was to develop a kit that would be affordable, easy to assemble and stand out aesthetically.

The content of the C3Jr kit is shown below (click for a larger picture).

It includes all the electronic components and mechanical parts to build the C3Jr clock shown in the next photo (on Justin's workbench).

The large display is based on a matrix of 16x8, individually addressable, white (or blue) LEDs. Beside lighting up small letters (one letter per LED) that make up words, the display can also be seen as a matrix of 16x8 pixels, which can show scrolling characters or animated sprites.

The time-keeping chip is the extremely accurate (max 2 minutes deviation per year), temperature-compensated, DS3231, with a 3V coin cell for backup (keeps the time when clock is not powered).

Here is a list of the parts:

• large (18cm x 23cm) PCB;
• ATmega328 with 28-pin socket;
• either 16MHz resonator or 16MHz crystal + two 22pF capacitors;
• 74LS154 and 24-pin socket;
• STP08DP05 and socket;
• DS3231, pre-soldered to the board;
• CR2032 (3V) coin battery and battery holder;
• 130 diffused white (or blue, on request) 5mm LEDs;
• 17 PNP transistors 2N5401;
• 4 decoupling capacitors 100nF;
• 100uF electrolitic capacitor;
• 17 resistors 100 ohms;
• 6 resistors 10K;
• 2 resistors 4K7;
• 2 resistors 1K;
• 2 resistors 680 ohms;
• USB type B (power) connector;
• speaker/buzzer;
• 6-pin right-angle male header used as FTDI connector;
• 4 right-angle push buttons;
• 5k potentiometer;
• set of laser-cut, black plastic, baffles;
• laser-cut acrylic faceplate with your favorite choice of font;
• laser-cut plastic backplate;
• set of standoffs, screws, nuts, washers.

The C3Jr kit is available for order here or in my store.
Here are the assembling instructions.

The schematic and board layout for C3Jr are shown in the images below (click on the image for the bigger version). The KiCAD files are available for download here.

(*) QlockTWO is an industrial product (as opposed to the amateur, home-made, C3Jr). Take a look at how it is manufactured.

North Carolina Maker Faire Preview

Justin just sent this photo from North Carolina Maker Faire, happening this weekend (June 18-19, 2011), with lots of clocks, some bigger, some smaller.

And here is an instructable on how to assemble C3Jr, available for sale as a kit here.
Vote here for your favorite project in the LED contest.

Spilling the beans - C3Jr

I don't usually do this: advertising a project before its completion. But the beans are out anyway :)

I have already received inquiries about ClockTHREE price and availability. Although I don't make this kit and I did not participate in its design, I would gladly redirect all questions to its makers, the WyoLum team, mainly Justin and Anool.

The latest news is that ClockTHREE (read my brief review here) is already available in their store as a "complete kit" for US$333. It may look expensive, but considering what is included, it may actually pass as a bargain. Just think of the following:

• stylish, unique, wall-mountable, well designed & engineered, hackable, Arduino-programmable, multi-color Word Clock, featuring alarm, day-of-week and temperature display, scrolling text, plus many function modes;
• 160 high-quality 10mm RGB diffused LEDs and 32 10mm diffused white LEDs;
• a huge (about 25cm x 30cm) PCB and a lot of electronic components, including an ATmega328 and a ChronoDot;
• a large set of laser-cut plastic parts for baffles and enclosure, and the laser printed faceplates;
• great (open source) software developed specifically for it.

The assembled ClockTHREE is also available for US$444 (they surely have an affinity for numbers :).

Now back to the beans: a simplified, and hence lower-cost, version of ClockTHREE is under development by the same great WyoLum team (I also joined in for this one). It was named C3Jr, as in ClockTHREE Junior. Its functionality will be similar: word clock, alarm, day of week, various display modes etc. C3Jr will be single-color (usually white; blue is also considered), just a bit smaller, and, hopefully, as elegant as its predecessor. The "C3Jr complete kit" will be priced at under $200 and available mid June (2011), just in time for MakerFaire North Carolina.

Stay tuned for more details.

Updated May 16, 2011

PCBs are in, shown below (photo by Justin).

Updated May 20, 2011
C3Jr assembled by Justin. I think it looks beautiful.

ClockTHREE completed!

My previous post on ClockTHREE, a while back, was about my first impressions. The work I did then, starting to assemble the clock, consisted in a lot of tedious soldering and did not require a lot of thinking and analysis. Yet, not surprisingly, the clock passed all the software tests.

Now that I received the long-awaited blue LEDs, standoffs and faceplates (thanks again Justin), I was able to finalize my ClockTHREE. And let me tell you something: this is the most under-rated Arduino-based project in the history of Arduino, seriously. I am just now impressed with the amount of work that went into this project, from designing the PCB, to writing the scripts to generate the faceplates, to developing the software/firmware. I did a few of my own and I know what goes into this kind of endeavors. ClockTHREE is one complex piece of engineering: electronics, mechanical structure, software.

Here are a few more observations:

• the top frame fits perfectly on top of the baffles (the inside baffles being a tad taller, to compensate for the thickness of the frame), holding them down and keeping them square (as shown in the next two photos);

Frame on top of the baffles:

• everything (top and bottom covers, faceplate, baffles and frame, board) is held solidly in place with just 6 sets of hardware (standoff, screws, washers);
• the software works impeccably right off the bat (I was going to set the RTC time using an older library, then I found the operating instructions);
• the software has quite a few features implemented already (e.g. setting the display color, few display modes etc);
• the visual aspect of the clock is as elegant as that of QlockTWO.

Justin and Anool did an impressive job on ClockTHREE. Come to mind Steve Wozniak's words: "I would have loved to have invented that".

A new kind of baffles

It started as a challenge, then it became an obsession: the baffles for my own version (still work in progress) of Word Clock, the grid that separates the LEDs from one another, so that every letter on top of a LED can be lit individually.

Baffles for Word Clock clones have been made before, see here and here (part of this and that instructables, respectively). These examples separate groups of LEDs rather than each individual LED. Justin and Anool of ClockTHREE fame raised the bar (they did not call it ClockTHREE for nothing :) with their individually addressable LEDs and the associated baffles, an elegant and remarkable solution, nicely integrated with the board and the case. Trying to replicate their results for just one prototype is both expensive (laser-cutting) and tedious (calculations, drawings, assembly). After a lot of thinking, I "invented" my own solution for the baffles, as shown in the photo below.

Basically, I used 40-pin female headers to separate the low-profile, wide-angle, LEDs. The headers are held in place by soldering them to the prototyping board. For the 8x14 LED matrix, I used about 40 headers, for a cost of about $12.


Generally speaking, designing and making the baffles is a feat. With so many choices, one needs to answer a few questions before designing them:

• what material should be used (cardboard, plastic, wood etc)?
• what manufacturing process would be the most appropriate (in terms of price, assembly time etc)?
• how could they be attached to the board?

Plastic is an obvious choice for the material:

• laser-cut (expensive, requires the assembly of the parts);
• mold-injected (perfect for mass-production; no assembly required: what you get is what you use);
• 3D printed (suitable only for prototyping; may be expensive).

Even after having the baffles made, the question of how to attach them to the board still remains. They need to be placed equidistant between the LEDs and held solidly in place (screwed down to the board maybe?).

Now you don't need to wonder anymore why Peggy 2 does not come with baffles :)

Weekend in Paris...

I wish.

This was another well spent weekend, inside, soldering. Lots of soldering, mostly LEDs.
I never built a LED matrix myself from discrete LEDs. (I actually started one for the "Word clock" on instructable.com, but never finished it.) I always took "for granted" (not literally; I paid for them) the 8x8 LED matrices or the LED displays from Sure Electronics. But this weekend I truly understood why the German-made (?) QlockTWO is as expensive as it is. Not only because of the design but also because of the amount of labor involved.

To cut through the chase, I started assembling the ClockTHREE. It's got 160 RGB LEDs organized in a matrix of 16x10. For those not familiar, ClockTHREE is an initiative by Justin and Anool to develop a better (multicolor, programmable) and open-source version of the above-mentioned QlockTWO.

This is how it looks so far (not finished yet, still waiting for a few components to arrive).

A few first impressions on the hardware:

• This is not your average project. Even though it may look like the "LOL shield" from a distance :), it is more than just soldering LEDs. Each RGB LED requires a bit of preparation (with the special wedge tool), then careful insertion and double checking with the multimeter. It is absolutely necessary to read the assembly instructions before starting soldering the LEDs.
• The PCB, one of the biggest I have seen offered in a kit, looks very professional. It's nice to see the component values (for example, "10K" for resistor) in the silkscreen. The layout is very well balanced, with parts placed around the LED matrix display area, buttons and connectors accessible at the bottom.
• There are a couple of surface-mounted ICs (the shift registers), which would require non-novice soldering skills. Note (from Justin): the actual kit will come with the SMDs pre-soldered on breakouts, which will allow for easy removal in case of testing/debugging.
• The rtcBOB, compatible with the ChronoDot, could be used in other projects as well, since it is removable (and connected through headers).

As shown in the photo, the board is missing the last two rows of LEDs. They will be populated with single color 10mm white (or blue) LEDs.