This instructable will show you how to make your own arduino based watch that tells time using a matrix of LEDs. This is my first instructable, so if something is unclear leave me a comment or send a message!

I was inspired by all the cool LED watches that I saw on this website:
http://www.tokyoflash.com/en/watches/1/

They have a lot of different designs that let you tell the time in very unique ways. So, I thought I'd try my hand at making my own LED watch using an arduino.

My watch design is very basic, but can be easily modified to create different LED layouts and different programming schemes. I am fairly new to arduino programming so for this instructable I will be using a modified code that I got from the Makerbot Watch project:
http://wiki.makerbot.com/makerbot-watch

I had big issues with the battery life of my first watch design, but with the modified Makerbot code and a larger battery,  the watch will tell the time for at least 12 hours on a single charge.  I am working on modifying the code to allow the watch to only display the time when you press one of the buttons. This should greatly increase the battery life. I will post it as soon as its finished. 

***EPILOG CHALLENGE***************************************
I have entered this Instructable into the Epilog Laser Cutter challenge. The laser cutter would come in handy when designing new watch faces and enclosures. The watch faces could be etched/cut with numbers or words to make telling the time much easier. Not to mention greatly improving the aesthetics. Also, the time it would take to make the watch enclosure would be greatly reduced, the dimensions would be more precise, and it would open up possibilities to use different materials. Overall, I would use the laser cutter to make a wide range of higher quality LED/Arduino watches. 
*******************************************************************

NOTE:
This instructable requires the soldering of very small surface mount components. If you are new to soldering, or have never handled surface mount parts before, I will try to explain as best I can how to successfully solder this project together.
 
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Step 1: LED Matrix

This watch will tell time using a total of 28 (output) LEDs, and be controlled by 3 (input) tact switches. Obviously, an ATmega328p does not have that many programmable I/O pins so some manipulation needs to be done to individually control all those LEDs. The buttons will be controlled by 3 individual pins. 

To do this, we will use a technique called charlieplexing, or display multiplexing. Basically, this method will allow us to use X number of pins to control X*(X-1) number of LEDs. For example, we can control 6 LEDs with only 3 output pins. This is possible by utilizing the tri-state logic properties of microcontrollers and the forward bias of LEDs. In other words, each pin can be set in 1 of 3 states: High (5 or 3.3V), Low (GND), or Not Connected (a high impedance state that disconnects the pin from the circuit).  Also, an LED will only light up and pass current to the rest of the circuit in one direction (from anode to cathode). The first four images will give an example of how charlieplexing works using 3 pins and 6 LED's.

Now, by expanding this basic layout we can create a matrix of 28 LED's that can be controlled by a total of 11 output pins. 

This is a relatively simple explanation of a complex process. If you would like more information, I found this instructable to be more comprehensive, and very well written. 


mrmerino says: Mar 16, 2013. 10:21 PM
Oh, I don't have a steady hand. What do I do?
jojox says: Feb 10, 2013. 2:21 PM
Hi
Great project, thank you for sharing.
Concerning the problem of compilation, it is simple to pay, simply replace the call Wiring. pm in the library Arduino.H
skellum says: Dec 1, 2011. 9:33 AM
The Bill Of Materials spreadsheet (Watch BOM.xlsx) transmits as a .tmp file ,which I can't seem to open. Is there another link?
mtawil says: Aug 4, 2012. 1:54 AM
Right click and open with excel
akellum1 says: Nov 30, 2011. 5:26 PM
The .cam file doesn't seem to download properly. Surely you could just let us download the completed .zip to be sent off to seeedstudio?
skellum says: Dec 1, 2011. 9:24 AM
Try the .brd and .sch files on the previous page!
carjo3000 (author) says: Nov 30, 2011. 6:14 PM
Thanks, I'll look into fixing the file. But, if you go here:
http://www.sparkfun.com/tutorials/109
they have the same file and a really good tutorial on how to install it.

I can't really give you a .zip file to send to seeedstudio because you first need to place an order with them for the boards then place your order number on the board's silk screen layer. So if I made the gerbers here for download, they would be missing the order numbers. Sorry about that

shane11 says: Nov 5, 2011. 11:09 AM
I don't seem to see the Hand-Made pcb image on here? Can you maybe point it out if there is? This project is amazing! I am making one right now with pin outs.
carjo3000 (author) says: Nov 5, 2011. 4:26 PM
Thanks for the comment! The handmade PCB image is the last one on Step 13. Its only of the top layer, and its fitted into my watch case. Let me know if you need some more details
shane11 says: Nov 5, 2011. 7:02 PM
Thank You! That is a great looking board! :)
lawrenceyost says: Oct 15, 2011. 9:13 PM
Hey buddy!Thank you first,It's a great project.But when i trying to do this.I found one problem that the program told me :MakerBotWatch has not been declared.
That's a big problem to me.So ,how can I fix this problem?!
Thanks!
carjo3000 (author) says: Oct 15, 2011. 11:15 PM
Make sure that you have the MakerBotWatch.cpp and MakerBotWatch.h files in your arduino library. The file names are case sensitive so make sure they are named properly. If that doesn't work, try downloading the latest version of arduino. If that still doesn't work, try downloading the watch code again and try running it.

Once you fix this error, you may also get an error when the compiler reaches the "boolean" line. To fix this, you need to download the arduino Frequency Timer 2 library. I've used this library on past projects so I forgot to mention it in the instructable. I will add it soon, but you can google it if you want.

Let me know if this works. And thanks for the comment, I would love to see how your watch turns out. Please post some pics!

lawrenceyost says: Oct 15, 2011. 11:42 PM
Thanks buddy!I found that the files name is so important in this project.Now I finish the programing.It wat lights up right now!It looks very beautiful!
I'll show you some pics later!What's your mail?What's your name?Where are you from?I just want to be a good friend with you!
I from HongKong! My name is Lawrence!
carjo3000 (author) says: Oct 15, 2011. 11:55 PM
Glad to hear you have it working, I can't wait to see the final product!
lawrenceyost says: Oct 16, 2011. 12:15 AM
Thanks buddy!I'm coming to show you the pics!
IMG_1091.JPGIMG_1096.JPGIMG_1097.JPGIMG_1098.JPG
carjo3000 (author) says: Oct 16, 2011. 12:31 AM
Wow that looks great! The board looks really nice in blue! What are your plans for the watch case? After seeing yours, I think I'm going to have my next batch made up in blue :)
lawrenceyost says: Oct 16, 2011. 12:46 AM
Did you did the project all by your hands?I found that's to much hard for me.I did the project used 38 hours!
lawrenceyost says: Oct 16, 2011. 12:44 AM
Ok,My friends.I thik I'd like use the glass for the case.But I think it's so hard to do that!How about you think?
carjo3000 (author) says: Oct 16, 2011. 1:04 AM
Well, I made my case entirely by hand, and it did take a long time to do. From your pictures, I notice that the corner mounting holes are missing. It would be hard to make it the way I did without the holes. But it should not be too hard to add them later on if you wanted.
If you look through my instructable, you'll see that I made the case piece by piece. But, I'm basically just making a box. So if you can find a plastic or metal box that can house the PCB (and still looks good to be on your wrist) you can just cut the holes for the buttons and watch band. Then, glue a piece of clear acrylic as the box top so you can see the LEDs. That's just one idea...
backyardengineer says: Oct 5, 2011. 8:54 PM
Have you thought of any other features you could add to this watch? I love the concept but you have so much more power that is wasted in just telling time that my $10 watch does.
carjo3000 (author) says: Oct 6, 2011. 10:27 AM
Thanks for the comment! I am working on more features to add to the watch, this is really just a starting point. Since it's basically an arduino, I'm planning on incorporating some sensors in a future design, such as temperature, humidity, and possibly pulse rate. Ultimately though, I would like to have it set up to where the watch becomes a portable arduino that you could easily plug into your computer, plug in some sensors, and upload a sketch, all while its still on your wrist. In the mean time, I think telling time with LEDs is pretty cool, and you could easily write some code to make the LEDs light up in different patterns if you wanted.
backyardengineer says: Oct 7, 2011. 8:07 AM
I agree it is a cool watch look forward to some sensors. I have also thought of doing one with a digital display myself, I wanted a few sensors that would help at work.
robot797 says: Sep 26, 2011. 3:20 AM
you will start selling those will you?
carjo3000 (author) says: Sep 27, 2011. 9:47 AM
I would like to sell them eventually. I'm working on different LED arrangements that tell the time differently. And it takes a while to make the watch case by hand so I'm looking into faster methods.
Ugifer says: Sep 27, 2011. 8:25 AM
This is a beautiful project and the fact that these boards look so professional really makes it.

Fab.
dimtick says: Sep 26, 2011. 1:58 PM
WOW. GREAT JOB!!!!!!!!
Way beyond my skill level.
looking at the band glue joint in the photo, it just doesn't look very strong to me and i don't know if the circuitry could take the drop if the band broke..
I wonder if keeping the band as one piece that either ran thru the watch or below it, with the watch being rivited thru the back, would hold up a little better?
would take some thought to deal with any clearance issues but it may be worth the effort since its clear you have plans to get this into production?
just a thought.
really nice work.
you've got my vote.
carjo3000 (author) says: Sep 26, 2011. 7:12 PM
Thanks! I actually tried running the watch band through the case as one single piece, but I had to make the case wider for everything to fit. I wanted a thin profile, so I nixed the idea for now.

The glue joint that I describe for the band has been working out pretty well so far. I have been wearing my watch mostly everyday for weeks now and so far so good. But you're right, the joint could eventually wear out. I'm playing around with different options. I was thinking of splitting the end of the strap inside the case and then gluing the flaps to the inner wall. Or, maybe crimping something to the end (like a staple) so that it can't be pulled out. These could work, but I am open to any ideas....
cnludwig says: Sep 26, 2011. 7:00 PM
This is an amazing project! It must have taken many hours!
trialex says: Sep 26, 2011. 3:24 AM
Dude!

Freakin' awesome instructable. Excellent details.

I have a half done design for an arduino watch with EXACTLY the same layout of hour LEDs, but your overall design incorporating the LiPo charger is just so much better overall I'm going to just stop working on mine and use yours - thanks for posting the design files!

Anyone interested in a group buy? I don't really need 10 copies...
jam BD says: Sep 25, 2011. 11:59 PM
An amazing porject and 'ible, Well done .
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