Wooden LED Clock - Analog Style

Intro: Wooden LED Clock - Analog Style

It's an analog style wooden LED clock. I don't know why I haven't seen one of these before..even though the digital types are very common. Anyhoo, here we go!

STEP 1:

The plywood clock project started as a simple starter project for the CNC router. I was looking at simple projects online and found this lamp(image above). I had also seen digital clocks that shine through wood veneer(image above). So, combining the two projects was an obvious idea. Looking to challenge myself, I decided not to use veneer but only a piece of wood for this project.

STEP 2: Design

I designed the clock in Inkscape (image above). The design is very simple by choice. I decided against routing traces for the wires because at this point I was unsure if I wanted to go with radial or perimeter wiring. (I decided to go with perimeter wiring finally.) One neopixel goes in each one of the small circular holes for showing the minute and hour time, with five-minute precision. The circle in the middle will be routed out to accommodate the electronics.

STEP 3: CNCing

I designed the toolpaths on MasterCAM, and used a technoRouter to mill out the clock from 3/4 inch plywood. I use a 15"x15" piece for this, with minimal wastage. The trick is to route out as much of the wood as possible without breaking through the wood. Leaving 0.05"-0.1" is a good choice for light wood. If you are unsure, it's better to leave more wood in, because you can always sand the other face. I ended up removing a little too much wood from some parts, but thankfully the results don't suffer too much because of this.

Note for users without access to a CNC:

This project can easily be done with a drill press. You just need to set the stop at a point where you leave around 0.1" of wood remaining at the base. You'll have to be precise, but not too precise. After all, ideally no one will see all the LEDs light up at the same time, so you can get away with a little slop.

STEP 4: Electronics

The electronics are fairly simple. There are 24 neopixels, twelve for showing the hours and twelve for showing the minutes, with five-minute precision. An Arduino pro mini controls the neopixels and it gets accurate time through a DS3231 real time clock(RTC) module. The RTC module has a coin cell as backup, so it doesn't lose time even when the power is off.

Material:

Arduino pro mini (or any other Arduino for that matter)

DS3231 breakout board

Neopixels in individual breakout boards

STEP 5: Electronics Assembly

I connected the neopixels in a string, using 2.5" wires for the first twelve leds and four-inch wire for the next twelve. I could have used slightly smaller wire lengths. After making the string, I tested it out, making sure the solder joints were good. I added a momentary switch to turn on all the leds, just to show off.

STEP 6: Dry Run

After experimenting, putting LEDs in the holes and turning them all on, I was satisfied with the results. So I sanded the front face a bit and applied a PU coat. I ended up sanding the coat off later on, but it's a good idea to leave it on if you don't find it aesthetically displeasing.

STEP 7: Epoxy

After some testing with the led position within the holes, I figured that the best discussion is achieved when the LEDs are around 0.2" away from the end of the hole. When you try this yourself, the brightness of the LEDs will be very different in each hole. Don't worry about this; we'll fix it in code. This is because of the type of drill bit I used. If I were to do this again, I'd use a ball end drill bit for the holes. But, in any case, to get the distance I mixed some epoxy and put a little bit in each hole.

STEP 8: Putting It All Together

The LEDs will be placed starting from the 12 o'clock hour hand position moving anti-clockwise through all the hour hand positions and then to the minute hand, again moving from the 60 minute mark moving anti-clockwise. This is so that when we view from the front the LED pattern appears going clockwise.

After the epoxy cured for an hour, I put in some more epoxy. This time, I placed the LEDs in the holes, making sure to cover the wires and solder joints with the epoxy. This makes for good light diffusion and secures the wires.

STEP 9: Code

The code is on GitHub, feel free to modify it for your use. When you switch on all the LEDs to the same level, the brightness of light shining through will be very different in each hole. This is because of the different thickness of wood in the holes and the difference in the shade of the wood, As you can see the wood color varies quite a bit in my piece. To remedy this difference in brightness, I made a matrix of led brightness levels. And decreased the brightness of the brighter LEDs. It's a trial and error process and can take several minutes, but the results are well worth it.

STEP 10: Computer Vision - Calibration

I made a conscious choice to not use veneer in this project. If I had, the wood thickness would have been the same in front of all LEDs. But, because I have a different thickness of wood in front of each LED and because wood color varies a lot as well, the LED brightness is different for each LED. To make all the LEDs seem to be of the same brightness, I devised a nifty trick.

I wrote some processing code(on GitHub) which takes a photo of the clock, and analyses the brightness of each LED in turn. It then varies the power to each LED to try to get them all to have the same brightness as the dimmest LED. Now, I know this is overkill, but image processing is a lot of fun! And, I'm hoping to develop the calibration code as a library.

You can see the LED brightness before and after calibration in the photos above.

STEP 11: Parting Remarks

Pitfalls to avoid:

* With wood, you get what you pay for. So, get good quality wood. Birch plywood is a good choice; any light solid wood will do nicely as well. I cheaped out on the wood and regret my decision.

* It's better to drill less than more. A couple of the holes went too deep for my piece. And the epoxy shows through on the front face. It's very noticeable once you notice it.

* Use a ball end drill bit instead of a straight end. I've not experimented with the ball end bit, but I'm pretty sure the results will be much better.

I'm flirting with the idea of selling these on Etsy or tindie. I'd really appreciate it if you could comment below if you think it makes sense :)

Comments

[danielsaldanasage]

Do you have a complete schematic of the electrical and electronics? Thanks

[Artuino]

You could have put numbers on the LED. nice job

[AllisonD37]

Did you install the analog clock after you ran the electronics?

[tinkrmind]

Oh no! There is no analog clock! That's just photoshopped to illustrate how to read the clock :P

[AllisonD37]

That makes sense. We have a beautiful piece of birds-eye maple plywood we've been holding onto for the perfect project. I think this is it. My husband is going to fabricate the wood piece, and we are giving it as a "kit" to our son-in-law for Christmas for him to build. Thanks for your reply!

[tinkrmind]

That's great! I'd love to see some photos :D

[aamen]

Hi, very good idea and design!!
I just have a doubt, is it dificult to tell the hour hand from the minute hand when they are far away from each other, like int the first picture?. Maybe use diferent colour for the leds would be better?.

[tinkrmind]

That's a good idea! They're neopixels so it should be fairly easy. I'm currently making an esp8266 controlled clock, so you'll be able to change the led colors online!

[voorkomen]

Hi, a nice modern world clock.

Some 40 years ago I built such a clock, that also included seconds. Micro processors still had to be invented as you can see from the pictures only discrete components and that day standard ic’s were available. At that time I noticed that time could not be determined in the dark. That is why I added a led in the middle which is continuous on and is a reference point to determine time in the dark. Short hand and long hand can be determined and seconds are obvious, because they move.

I would love to replace the circuit board with an Arduino, but did not yet find time.

[tinkrmind]

Oh my God! This is amazing. Thank you so much for sharing!! I was surprised that I couldn't find any clocks like this online since it seems like such a straight-forward idea. You should really write a blog post about it!!

Having an led in the middle is Genius by the way. I'll probably stay away from it, maybe do an edge light to show the outline instead.. but it's just an artistic choice on my part.

[voorkomen]

It’s history. To short cut: I’m not a blog writer while appreciating those that do! It sounds strange, but since I’m retired it seems difficult to find time. So much things that I parked during my working time and pick up now. CNC, 3D printing, SMD soldering are things that I have (love) to learn and that takes time, apart from playing badminton, letting our dog out, doing the things that have to be done and last but not least spending time with my wife children and grand children. But maybe I’ll do when translating my original schematics to Arduino. Then I would also feel committed to include GPS or at least a real time clock for time setting since now it is based on 50Hz power-line frequency.

So let’s see what the future brings.

BTW you should use the pointer lasers in each corner that will cross in the center.

[tinkrmind]

You should be proud that it's working as much as it is despite being a forty-year-old project! Kudos!

[voorkomen]

First things first. To day going on holiday with my wife to Morocco!

[tinkrmind]

Thanks again for sharing! I'd love to help out if you ever decide to convert to an Arduino setup :)

[tinkrmind]

It's a sad truth that we makers often neglect everything except for 'the project' to the peril of health, wealth and relationships. It's good to maintain a balance and you should never have to justify yourself for that!

[voorkomen]

One other thing I came across is the moment to go to the next hour.

First I had it when minutes reached 12 o’clock which seems logical. But then the clock would show first half hour correct, but second half hour wrong (though “analog” it is still digital!) i.e. changing from 3:59 to 4:00 and after that would show 4:29 still “correct” until 4:30. After that it would show 29 minutes to 4 which is obvious not correct. As shown the best possible solution for me was to change hours each half hour. Also possible would have been to put 24 (or better 60) LED’s in the hour circle, but that would have ment at that time building a complete new clock.

(PS It can be seen, that this old clock is not working as intended and did 40 years ago).

[inconceivable1]

cool!

[tinkrmind]

Glad you liked it!

[DoofusOfTheDay]

I think it would be easier for most to drill straight through for the holes, then glue a piece of veneer on the front. You'd have consistent thickness of the wood and with veneers you can get some fantastic looking species of wood.

[johsou]

i like that