Wooden Chain Clock

I have had the idea for this clock for a while since i saw a similar one on the internet. The Time Contest was the motivation i needed to get it off the drawing board and actually create it. This is the first clock I have built and my first instructible so be gentle.

Parts Required

• 1x Nema 17 stepper Motor ( the ones im using are 200 step bipolar)
• 1/4in Plywood (I use Baltic Birch, seems to work well)
• 1/8in Plywood or hardboard panels or Plywood for the letters and chain. I used this from amazon.

http://www.amazon.com/Hardboard-Panels-12x16--Pack...

• 2 x 220mf Capacitor

• Holdding DS3231 Arduino Real Time Clock

• Arduino Uno

• Small breadboard or Protoboard

• 100 x M3 x 12mm Screws for the chain

• 100 x M3 Nylon Locking nuts

• 1 x M6 x 50mm Screw

• 1 x M6 x 35mm Screw

• 5 x M6 Nuts

• 10 x M3 x 20mm Screw

• Wood Glue

• A4988 Stepper Motor Driver

• 1 x 2.1 x 5.5mm DC Power Male Connector Plug

• 1 x 5.5mm x 2.1mm DC Power Cable Female Connector Plug

• 12v 2a or more dc transformer

• Superglue

• Wood Glue

I own a Boss 60w CO2 Laser so the settings might be a little different for other lasers.

1/8in hardboard 17mm/s 95% power

1/4in Plywood 9mm/s 95% power

The edges of the chain gears need to be beveled to allow the chain to easily rotate. The best way I have fouind is to use the M6 bolt and a nut and 2 washers to attach the gear to a cordless drill. Rotate the drill while sanding with a dremel. This will get all the edges beveled the same amount the quickest. There is probably a better way to do this but i haven't found it.

Now to assemble the frame. First add the little wooden spacers that go between the front and back pieces of the frame. Then add the m3 nuts into the spacer thingys with pliers and insert the m3 x 20mm screws into the holes and into the nuts.

Then we will superglue the nylon standoffs into the holes for the arduino.

Insert the M6 bolts through a washer and then through the holes in the frame as shown in the picture then tighten a nut on each one.

Mount the Nema 17 Stepper motor into the frame with the M3 x 10mm Screws.

For the far left gear.

This is the biggest gear,put the gear on an extra bolt, then put a dab of glue around the center and add a put a 1/8in spacer on the bolt, then a 1/4in spacer, then another 1/8in spacer. Then add one of the chain gears and washer and nut it. Tighten the nut so that the glue between all the layers can dry properly. I made a video of this process on one of the gears and embeded it so you can see what im talking about. after the glue is dry remove the bolt and put a 1/8th spacer on the spindle and then the gear assembly on the spindle.

For the middle gear.

Glue the solid 20 tooth gear to the 60 tooth gear using a bolt to align and allow to dry. Mount to the center spindle with 1/8in spacer.

For the Right gear (drive gear)

Fit the D shaped spacers onto the stepper motor and glue. Then glue the chian gear to 3 1/8in spacers and allow to dry. This is the one im doing in the above video. center and glue the chain gear to the stepper motor and clamp. Make sure you center it properly or it will wobble. Use double nuts or M6 lock nuts so that these gears do not come loose.

Ok , now for the electronics.

The easiest way to describe the electronics is to show you the schematic. Just plug it all in as the picture shows.

Mount the arduino into the frame using the nylon snaps.

The arduino coding was tricky and required the help of an expert (my business partner). we incorporated the real time clock into the programming and made it so we can change x steps per x seconds, so the same program can be used for different variations of clocks.

After the coding and uploading is done test the unit to make sure that it moves every 45 seconds. if it does then unplug it and install the backplate to complete the frame assembly.

Now for a time consuming task. assembling the chain. Just start at 1 on the hour side and add three links in between each number.

When you have the chains completed set it on the gears so that one of the hours is on top on the left and 00 is on the right gear. Then turn the right gear to the correct time before plugging the unit in.

This is my first clock, i would love to make more intricate clocks in the future. Please Vote for my instructible in the TIME contest. Thanks for reading. I also have this kit availiable for purchase if you do not have a laser cutter availiable. http://www.makrtoolbox.com/chain-clock-kit.html