Bicycle Chain Clock (Low Part Count)

Hello everyone,

This was a project that I've been wanting to take on for a while and when I came accross an old bicycle chain in a store room I knew I just had to make this.

I wanted to have the part count as low as possible so that replicating this project would be easy.

To build this clock you will need:

• Bicycle chain, the length will depend on how long you want your clock to be.
• Stepper motor.
• Arduino, the arduino nano fits in the enclosure.
• Stepper driver, a4988/easy driver etc.
• Power source, 12V/5V depending on your setup.
• Hammer.
• Punch/Nail to break the chain apart.
• Access to a 3D printer.

If like me you are going to be using an old chain it will need a good cleaning.

The chain I got was rusted quite a bit and did not want to move freely so I left the chain in a bucket of diluted vinegar overnight to get rid of the rust. In the morning I rinsed it, dried it off and gave it a good spray of WD40 to prevent rust from developing again.

Now with a clean chain we want to start breaking it up into 12 equal lengths. I broke mine into 13cm lengths.

If you are lucky enough to have a chain breaking tool this step will be a lot quicker, otherwise like me you can use a hammer and punch to hammer out the pins holding the links together.

To do this place your chain link on either a block of wood with a hole drilled under the pin or a bench vise, centre your punch on the pin in the link and hammer it out. Be sure to keep all of the pins as you will need them to assemble the chain again. Your pieces need to have open links on both sides as pictured.

Next we need the numbers, spur gear and enclosure. I opted to 3D print everything for the clock but it can also be laser cut.

All parts were made in Tinkercad and then printed in antiqued gold ABS.

This is a quick print with no difficult parts.

Thingiverse link

The teeth of the spur gear will need to be sanded a bit to get a smooth movement.

I will update the Instructable with any updates in the future.

Like the rest of the project I wanted the movement of the clock as easy to replicate as possible.

I used only 3 components, the arduino, a stepper motor and driver. A real time clock module can also be added if you want to increase the accuracy of the clock.

Pin 13 on the arduino goes to the step pin of the driver.

The Dir pin on the driver is grounded.

The arduino receives 5V power from the on board voltage regulator of the easy driver.

The code is as easy as it gets:

/*
Basic Chain Clock

This is a simple code to pulse pin 13 HIGH and LOW in order to drive a stepper driver like the Easy driver or A4988

Adjust the LOW state to adjust the speed of your clock. *

/ the setup function runs once when you press reset or power the board void setup() { // initialize digital pin 13/LED_BUILTIN as an output. pinMode(LED_BUILTIN, OUTPUT); }

// the loop function runs over and over again forever void loop() { digitalWrite(LED_BUILTIN, HIGH); delay(1); digitalWrite(LED_BUILTIN, LOW); delay(13333); }

You only have to adjust the LOW delay according to the chain used in your clock.

Now we can start the final assembly of the clock...

First we need to assemble our chain.

TIP: After a lot of struggling I took a Dremel with an abrasive disk to bevel the one side of the chain pins (see picture) this made assembly a lot easier as there was no more resistance when pushing in the pins.

Start with "1" place the number in between the two open links of your chain, align the hole of the number and link and then hammer in the pin. Do this with the rest of the numbers in sequence, once you get to "12" you connect the last link to the start of "1" to close your chain.

Next you can fix the stepper to the enclosure with 4 M3 screws and arrange the electronics in the cavity.

The final step is to push the spur gear onto the shaft of the stepper motor and then screw in a picture hook into the raised part on the back of the enclosure...That's it you're done with the assembly.

Hook everything up, throw on the chain, power her up and marvel at your brand new creation ticking away!

To adjust the clock I start by aligning a number with one of the teeth at the top of the clock then I turn it until the current time is shown at the top of the clock.

* I will update the Instructable with a video of the clock in action as soon as it is in its permanent spot.

Happy making!