Single Chain Clock

I have always had a fascination with clocks, The constant movement, the timing, and the art. It is beautiful. It has always been my way of integrating Technology and art. My first instructible was a wooden chain clock. I had so much fun making it that I have thought of several different improvements that I can make to create a completely new clock.

This clock Incorporates a single movement on the hour hand that also shows the minute by showing the minutes as a gauge. I chose to use acrylic and a metal chain for this project as I thought that using the metal bicycle chain complimented the look of the black acrylic.

I really enjoyed making this and I hope you will as well.

These are the parts, materials, and tools that I used to assemble this clock

Parts Quantity

1. Nema 17 Stepper Motor --Amazon 1
2. A4988 Stepper Motor Driver --Amazon 1
3. Female DC jack -- Amazon 1
4. Male DC Jack -- Amazon 1
5. 220uF 16v Capacitor -- Amazon 2
6. M3 x 8mm -- Amazon 4
7. M3 x 12mm -- Amazon 24
8. M3 x 16mm -- Amazon 6
9. M3 x 30mm -- Amazon 2
10. M6 x 30mm -- Amazon 3
11. M6 x 50mm -- Amazon 1
12. M3 Nuts -- Amazon 6
13. M6 Nuts -- Amazon 8
14. M3 Washers -- Amazon 48
15. M6 Washers -- Amazon 12
16. M3 Lock Nuts -- Amazon 26
17. M6 Lock Nuts -- Amazon 4
18. Arduino Uno --Amazon 1
19. M3 Brass Standoffs -- Amazon 4 Or
20. 3mm Nylon standoffs - Ebay 4
21. 12v Power adapter --Amazon 1
22. Small Breadboard --Amazon 1
23. Arduino Real-Time Clock -- Amazon 1

Materials

1. 1/8in White Acrylic -- Amazon
2. 1/8in Black Acrylic -- Amazon
3. 1/8in Clear Acrylic -- Amazon
4. 1/4in Black Acrylic -- Amazon
5. Bicycle Chain --Amazon 1 1/2
6. Wire Jumpers -- Amazon
7. Super Glue -- Amazon

Tools

1. Laser Cutter --- This is my laser cutter, I have been very happy with it and the customer service is great.
2. Dremel Tool With Cut off Wheel and Sanding wheel
3. Cordless Drill
4. Chain Break Tool -- Amazon

Way back before I even had a workshop I always said that I wanted to own a laser cutter, a 3d printer, and a CNC Router. Soon after getting my workshop I got my first 3d printer. Then I used the 3d printer to build my first laser cutter. I Love my laser, I would highly recommend to all makers out there, save your money and buy one.

Anyway, step one is to cut all the parts. Here is the sizes and colors that I used to build this clock.

All of the DXF files are available for download on this page, as well as the original corel draw file so that you can make changes if you want to.

1. The Backplate / Frame is 1/4in Black Acrylic
2. The Numbers are 1/8in Red Acrylic
3. The Number accents / Arrows are 1/8in White Acrylic
4. The Gears are 1/4in Black Smoke Acrylic
5. The Spur Gear and Minute gauge are both 1/8in Clear Acrylic

Before I mount the numbers on the chain I will peel the film off of the numbers. Acrylic has a film coating that keeps it from getting scratched. So after the film is peeled off then I glue the White arrows onto each of the numbers. I do have some acrylic weld that I thought about using to put the arrows on the numbers with, but I decided to use regular super glue instead. It seems to work great so long as you do not use too much.

So because I am starting with a whole unbroken chain, I need to use the chain break tool to break the chain at certain intervals so that I can insert the numbers. The way that I designed the clock there is a hour every 12 links. So the chain links need to be 11 links long.

It took about 1 1/2 chains to get the 12 sections of chain that I needed to complete the clock. Now that I have the sections of chain cut I can start to put it together. I started at the number 1 and bolted it on. I used the m3 x 12 hex head bolt from the parts list in step 2. So it seems to work best when I included a washer on either side of the numbers. So just to clarify, if looking from the top is is chain, washer, acrylic number, washer, chain. LOL That is confusing. Just look at the pictures, I have faith that you will figure that out.

So putting the chain together is by far the most time consuming part of this build. As I am putting the chain together I think "isnt this why I have Children?". So in the future, the kids are putting the chains together for me. I will call it "family togetherness time" or "lets play Malaysian sweatshop". I forsee that lasting about 5 minutes before "dad this is boring", dang kids these days.

The spur gear (the one that the chain rides on, needs to be beveled so that the chain will properly ride on the gear. The easiest way to bevel the edge on this gear is to put one of the m6 x 30 through the hole and nut it tight. Then chuck it into your cordless drill and run the drill and the dremel tool at the same time. See the above photos to see me demonstrate this step.

The Math

So the math of these clocks always makes my head hurt. I will do my best to break it down for you. The Nema 17 stepper motor that I am using for this clock has 200 steps, that means that in order to make a full 360 degree rotation it will go 200 steps. The gearing on the clock is set so that one full rotation equals one hour passage of time. You cannot tell a stepper motor to turn any fraction of a step, but, you can do micro-stepping. Micro-stepping is a function that is enabled from the stepper motor driver (in this case it is the A4988). Micro-stepping enables the stepper motor to move in fractions of a step, namely half, quarter, eighth, and sixteenth step. If I were to leave it at a full step then we would need it to move 200 steps in 60 minutes, which equals 3.3333, since we can not do parts of a step I will use Micro-stepping. If I use half Micro-stepping, I have 400 total steps I can move for a full rotation. 60 minutes x 60 seconds is 3600 total seconds in an hour, divided by 400 steps is 9, so I will set the code to 400 steps using half micro-stepping, and it will move 1 step every 9 seconds. This will acheve the 400 steps every 1 hour.

Breadboard Or Solder Board

Another question I often ask myself is wether to mount the electronics on a breadboard or a solder board. What I usually do is use the breadboard first and make sure everything is working and then I move all of the electronics over to a permanent solder board.

The code that I am using for this project was originally made for my wooden chain clock that I made last year. The code was developed in such a way that there are three adjustable variables.

Code Variables

1. Total Steps, 200 for full step, 400 for half step, 800 for quarter, 1600 for eighth, and 3200 steps for sixteenth step.
2. Steps , How many steps do you want to move
3. Seconds , How often do you want to move this many steps

With these three variables this code will work with any clock that uses a single stepper motor. For this project the variables are set to

1. Total Steps 400
2. Steps 1
3. Seconds 9

The finished Code is available to download in .ino file.

Before I pulled the film off of the gauge acrylic I Painted the gauge with blue acrylic paint, filling the engraving with paint. When It is dry I Pulled the film off and was left with the clear gauge with blue lettering, I really think that this looks a lot nicer that plain engraving. After Looking at the clock on the wall I painted another gauge white, so it would stand out better.

I am sure that there is a name for this thing, please tell me in the comments. But because I am not sure what it is called, I am calling it a gear holdy on thingy. So there. I have a lot of 3d printer parts, so I am taking the stepper motor belt drive and taking a dremel and chopping off the belt drive part, keeping the part that uses a set screw to mount to the motor shaft. By putting one of these on either side of the gear, The gear will stay where I want it to.

The Frame is pretty easy to assemble, everything gets bolted onto the main base and then the back will go on last.

Start with the m6 x 30 bolts and put them through the three gear holes towords the top, and put a washer and then double nut them all. The main shaft that the chain will be on uses a m6 x 50mm bolt and will also be washered and double nutted (is that a word?). Then you can put another washer and then the gears, then another washer and then the lock nut. Do not over tighten the lock nut or the gears will not move.

The stepper motor is mounted with 4 M3 x 8mm bolts. Then the Main Gear needs to be assembled, it is the large toothed gear, then 3 spacers, and then the spur gear, Held together by 2 M3 x 30mm bolts with lock nuts on the back.

The Minute guage gets attatched using 2 M3 x 16mm bolts and nuts held in to place. Then the only thing left is to hang the chain and plug it in.

The chain ended up weighing a lot, so I added a small piece of wood to the bottom of the frame so it would sit straight on the wall.

Pick your colors carefully, trust me. I made another chain in red, because it turns out that black numbers over black gears, and a black frame, is not so readable (who would have thought???).

I made several clocks and several chains, they look completely different with the different color chains.

I had a blast building this and I hope you enjoyed reading this. I appreciate your vote in the contests if you liked it.