Step Clock

More information about calibration and complete assembly instructions with pictures can be found at makitpro.com

Description

I have been wanting to use some stepper motors to design a clock for a long time, and finally I could find some time and IT IS HERE!

It uses two steppers to move hour and minute hands independently with 3D printed concentric shafts, while one Arduino compatible board controls everything.

For me, there were two big challenges; designing the concentric shafts and the position detection system. I spent quite some time thinking about the design before the first approach. Then, when I printed the first version, I decided to change some major things to make it easier to assemble. Finally, after a couple of prints and tests, I’m quite satisfied with this final version. It uses two hall sensors to know where the initial position is and a concentric shaft system with bearings. It also uses a real time clock module to keep track of the time when it loses power, so you only have to set it the first time or when changing batteries.

You’ll find different “faces” (covers), so you can choose the one you like the most, or have different models ready for swapping them depending on the occasion.

In addition, they are stackable, so you can print a couple of them and create some unique layouts and keep track of different time zones!!

Printing settings

All parts print without supports. The body is a long print (about 6-7hours). I decided to design it with 1.6mm wall so it prints with 4 perimeters (on 0.4mm nozzles).

I used PLA and printed all parts (except body) with 0.2mm layer height (body 0.3mm) and “standard” settings (3-4 perimeters and around 20% infill).

For the cover, there are two versions, the “normal” cover is supposed to be printed at 100% infill. On the other hand, the cover_infill part, is designed to be printed with different infill patterns and no top layers. Tinkering with the slicer settings, you can get some awesome original designs! With Simplify this is really easy to do, but if you’re using some other slicer you’ll need to change your printing settings accordingly.

Parts and components

In addition to the printed parts, you’ll need:

• 2x steppers with drivers: 5 pack
• Any Arduino UNO or MEGA board will fit, but I'd recommend this Arduino compatible board because of the extra SVG pins and contrasted quality.
• 2x A1302 hall sensors
• RTC clock module like this or this
• Dupont cables: Male to male, male to female
• 4x Neodymium magnets 4mmx2mm round
• Hot glue
• M3 screws and nuts, some countersunk and some button head 
• 2x bearings 18x12x4mm (outer x inner x thickness)
• 2x bearings 16x8x5mm (outer x inner x thickness)

Code

NOTE: Bear in mind that at the time of the release, the code is in beta version. It works but it may have some bugs/errors. Visit my github for latest updates.

The Arduino program is provided with the download (updated 13-7-17), but latest version can also be downloaded from my github repository.

You’ll need three libraries: RTClib, Accelstepper and wire.h that is already included with Arduino IDE.

If you like it please click “like” to support my work and don’t forget to post some pictures of your print!!

Assembly instructions:

More information about calibration and complete assembly instructions with pictures can be found at makitpro.com