Have you ever seen something on TV and though “If only that existed in real life”? Most people have, but most people don’t take the next step and go about building the object from scratch.
This is exactly what Andy, the maker from the electronics blog Workshopshed did when he saw the Topsy Turvy Clock on an episode of The Mr. Men. The idea is that the numbers are randomly placed but the time is still accurate – Andy thought he could make it work, but not without a solid game plan.
More directly from Andy:
I quickly realised that a conventional clockwork mechanism would be almost impossible to build but an electromechanical version with stepper motors should be achievable.
I already had some experience with the Arduino so decided to base the electronics around that. Prototyping has been done using a Arduino Uno but a smaller model has been bought for the finished clock. I sourced a small “real time clock” RTC module and some miniature stepper motors with some driver modules thrown in. As the stepper motor had a gearbox, I added a slotted optosensor so that the position could be detected. A defective mantel clock was purchased from a charity shop as I did not want to wreck a working clock.
Because the microcontroller would be responsible for the position of the hands the mechanical aspect is quite simple. I have tried to design it so that it can be made with my basic workshop equipment. The concentric shafts will be made on the lathe from metal but it could also be possible to use off the shelf tubing if you could find it. I wanted the chassis to be in brass so that it looked like it was part of the original clock so some thick sheet was purchased at a model engineer show. Plastic gears were chosen as they are cheaper and quieter when running than metal gears.
To follow all of Andy’s Topsy Turvy progress and watch an illustration become a reality, you can keep an eye on his blog.