Intro: Magnetic Clock
This instructable was created in fulfillment of the project requirement of the Makecourse at the University of South Florida (www.makecourse.com)
This clock was designed to be a unique and minimal time display that is as functional as it is nice to look at.
Two magnetic balls are pulled along the face of the clock using the custom 3D printed designs that are provided. At the end of every hour the minute hand is pulled back to the beginning of it's path. The hour hand does the same when the hour rolls over from twelve to one o'clock. There is a lot of potential to make many unique designs based on this model. A different piece of wood and different number indicators would make every clock one of a kind.
Step 1: Hardware/Software
- Microcontroller - Arduino UNO
- (2) Digital Servo Motor - LewanSoul LD-3015MG
- RTC - Diymore DS3231 AT24C32 IIC High Precision RTC Module Clock
- LCD - LGDehome IIC/I2C/TWI LCD 1602 16x2 Serial Interface
(2) Neodymium Magnet - N52 1" Cube Permanent Magnet
(2) Magnetic Balls - 1" Magnetic Hematite ball
(2) Buttons - Flush Mount Momentary On Off Reset Push Button Switch
Small nuts and bolts
Step 2: Printing the Parts
These are the files I used. They work as is but I did not leave a hole for the LCD screen because I added it in afterwords. Take care in cutting this hole if you want to include it. I recommend using a blade attachment for a soldering iron for clean cuts.
Step 3: Wiring
Take your time with the wiring and secure the components inside the printed incasing. I put a small amount of super glue on nuts and carefully glued them in place, that way I could unscrew and remove components if necessary. The Fritizing diagram for this control system shows a breadboard but securing all the wires that go VCC together before plugging them into the Arduino saves a lot of space. Do the same to the ground wires. There is enough space in the design to fit batteries if you don't want to have to keep it plugged in. I plan on doing this addition soon and I will update this page when I do.
Step 4: The Clock Face
After preparing the surface and attaching the parts on the back of the wood you are able to line up and mark where the ball's paths will be. I sketched out my design of graph paper then I used a glue stick to glue it to the face. I used a Dremel tool with a carving attachment to cut through the paper onto the wood.
If you've never worked with epoxy before, do a test piece first! There is a learning curve to all things and it would be a shame to ruin all the work you did thus far.
Epoxy is a polyepoxides that comes in two parts. These chemicals form a long chain when combined together and need to be proportioned correctly. Read the instructions AND FOLLOW THEM! The two parts need to be perfectly mixed together, otherwise it will not cure correctly. I added some makeup pigment to mine to match the magnetic balls. It looked great in the mixing cup but I wish I would have done it a little darker. The epoxy is translucent so the shallow sections don't look as dark.
Once you fill the holes you can pop all the bubbles by running a plumbers torch (or long grill lighter) quickly over the epoxy. Keep the flame moving! Alternatively, you can also use a straw and blow on them, the CO2 will pop them but beware of condensation from the straw dripping on your pour.
Once it as fully cured (read directions) use a palm sander to remove excess epoxy and sand the top smooth. Taking care to not pour too much in the first place will save you a lot of work.
I like these legs because the clock can lay down, stand on it's side, or stand up vertically on end. I attached the legs by using wood glue and putting screws in the corners. Pre-drilling the holes is the key to not splitting the wood. I started with a hole the size of a screw head and drilled about halfway through, then drill through the top and into the legs with a bit that is the diameter of the screw shaft but smaller than the threads. After I attached the legs I used a oak dowel and a little wood glue to plug the holes. Once everything dries, cut the plugs flush with the face and sand everything down.
I like to use butcher-block conditioner for this type of project. It makes a nice piece of wood look gorgeous, it's easy to apply, and non toxic. Put it on heavy and let it soak in, then wipe away the excess until it's dry to the touch.