CNC Machined Wood Clock

Hello,

I am a mechatronics student at the Cooperative State University (DHBW) in Stuttgart, Germany.

In this Instructable, I will show you how I built this unique wood clock.

If the clock is turned off, you can only see a normal piece of wood. As you turn it on, the numbers suddenly appear on the plate. It is very beautiful to watch.

The clock consists of a wooden front pannel and back pannel and is around 170 by 400 millimeters in size. The front pannel has many machined pockets with a bottom thickness of only 1mm. These pockets are arranged like a digital clock. LEDs mounted on the back pannel can shine through the thin wood and let it glow very beautifully.

The brain of the clock is an Arduino Nano combined with a real-time-clock module. This module has a small battery to keep track of the time even when the clock is turned off. A light sensor connectet to the Arduino measures the brightness of the environment so that the power to the LEDs can be adjusted automatically. For simplicity, an LED-strip is used instead of individual LEDs. The clock is powered by a USB cable. By using a power adapter it can be plugged directly into the socket.

Tools

• CNC router
• soldering iron
• Fusion 360 CAM/CAD

Supplies

• LED Strip: WS2812B 1 meter, 60 LEDs
• real time clock (RTC): DS3231 module
• Arduino Nano
• light dependent resistor (LDR): GL5516
• wood
• threaded inserts M4 for wood
• 4x M4 screws
• some wires

You can use any type of wood you like for the front and back pannel. I just used what I had laying around. The thickness should be around 8 to 25mm.

Now, I layed the wood in my homemade CNC router and made sure that its perfectly leveled. If you don´t level it properly, the wood will get to thin or thick at the bottom of the pockets.

After this, it was time to mill the pockets with a bottom thickness of only 1mm. The speeds and feeds can´t be too aggresive because the thin wood could break easily. Now I drilled the holes for the threaded inserts to screw the front and back pannel together. After this operation, I cut the outside profile.

The milling operations of the back pannel are quite similar to the front pannel. The difference is that the pockets have a different shape and are not as deep. They are just used to fit in the LEDs and electronic components. The back pannel is smaller than the front pannel which makes the clock more beautiful. The hole in the middle is needed to access the battery of the RTC when the clock is screwed together.

It´s now time for the electronics.

First, I cut the LED strip into segments of 2 and two single ones for the dots. I glued them onto the back pannel at their proper positions. After this, I soldered the strip segments together mostly with some unisolated wires according to my schematic. The Data-Out is connectet to the Data-In of the next segment, starting with the segment number 1. It´s important to solder them in the correct order. This process took a while (nearly 200 connections to solder) and had to be done carefully.

Now I placed the Arduino, the LDR-Lightsensor and the RTC into position and soldered everything according to my schematic. I had to bend the LDR, so that it fits perfectly to the front pannel. You can use some glue or tape to keep cables in place.

To power the clock, I cut an old USB-A cable in half and removed the insulation. I soldered a longer wire to the Vcc (red) and ground (black) wire. You can use any type of usb cable. You could make the clock USB-C powered. Now, I placed the long cable into the slot of the back pannel and added some superglue to hold it in place. I soldered the Vcc wire to the 5V pin and the ground wire to the ground pin of the LED-strip/Arduino.

To upload the code, you either have to disconnect the Arduino from the LED strip or plug both the Arduino and the USB-power-supply-cable into your computer. This is because the Arduino can´t deliver enough current to power all LEDs at full power.

There are two ways to set the time in the code. You can set the time manually or use the clock of your computer. In both cases, you have to upload the code twice. On the second upload you must remove one line of the code. Otherwise the time will be wrong after you unplug the power cable of the clock.

If it´s to dark in the room, the clock switches to night mode. After reaching a certain threshold, the clock switches to day mode. You can adjust both switching points as well as the different power levels in the code. It´s also easy to change the color of the LEDs. Feel free to experiment with these parameters.

You can change between 12 and 24 hour format by adding/removing line 111 of the code.

If the battery of the RTC runs out and the time is wrong, you just have to upload the code again.

It´s now time to screw the front and the back pannel together. To mount the clock onto the wall, I screwed in a small hook that grabs into a nail in my wall. You can also build some feet for the clock if you dont want to put it onto the wall.

Now you have a beautiful unique wood clock that, as far as I know, can not be purchased anywhere!

The combination of wood and electronics can lead to fire. It is always good to add a fuse with a rating of less than 1 amp to prevent a fire. I didn´t use one, because i use a power adapter with a very low current output.