My brother is a huge fan of Terry Pratchett's Discworld series. His favourite character is Lord Vetinari, who is the ruler of the city-state of Ankh-Morpork. A few years ago I made him a version of the clock hanging in Lord Vetinari's waiting room following this instruction. What makes this clock special is that even though it shows the right time in terms of the minutes and hours, the seconds seemingly at random go sometimes too fast and sometimes to slow in order to make people feel uncomfortable. I posted a more detailed explanation of the clock on step 2.
While my brother was really happy with the clock I made, I wasn't. I used a cheap IKEA clock which just didn't look the part (I changed the background to black, but that was about it.). Also it was having problems moving the hand indicating the seconds, since apparently the mechanism wasn't strong enough to move it upwards, when it moved faster than normal. The third thing that bothered me was that the clock is described to tick normal most of the time while only sometimes it doesn't. With the clock I built every tick seemed to be random.
So I decided to spend some time designing and building a second version of the clock. In this instructable I am going to show you how to make your own.
By the way, please don't make the same mistake I did and travel with the clock by plane. I also had a few glasses of self-made hand scrub for my mum in my luggage and together they looked suspicious enough for me being questioned for a long time.
If you are bored you can watch the clock running for five minutes in this video:
Step 1: Description of the Clock
The clock in the Lord Vetinari's waiting room is described in two different books:
"Someone very clever [...] must have made the clock for the Patrician's waiting room. It went tick-tock like any other clock. But somehow, and against all usual horological practice the tick and the tock were irregular. Tick tock tick... and then the merest fraction of a second longer before ... tock tick tock... and then a tick a fraction of a second earlier than the mind's ear was now prepared for. The effect was enough, after ten minutes, to reduce the thinking processes of even the best-prepared to a sort of porridge. The Patrician must have paid the clockmaker quite highly."
Terry Pratchett, Feet of Clay
"The clock in Lord Vetinari’s anteroom didn’t tick right. Sometimes the tick was just a fraction late, sometimes the tock was early. Occasionally, one or the other didn’t happen at all. This wasn’t really noticeable until you’d been in there for five minutes, by which time small but significant parts of the brain were going crazy."
Terry Pratchett, Going Postal
As you can see, only the mechanism of the clock is described and not how it looks. So my version shows how I imagine it could look like.
I decided that I wanted the clock to show the Vetinari family motto, si non confectus, non reficiat ("If it ain't broke, don't fix it."). Also I wanted it to look very simple yet elegant and black had to be the main colour, paying homage to his coat of arms which is described as a plain, simple, black sable shield, as well as his way of dressing in dusty black.
I ended up building three different version. At first I couldn't find a clock I liked, so I decided to 3D print my own. Afterwards I found a rather simple clock and decided to build a second version.
Step 2: Designing the Clock Face
The Vetinari family name is a pun on the real-life family of the Medici. The House of Medici was an Italian banking family and political dynasty. In order to decide on a font for the Vetinari family motto I searched for Cosimo de’ Medici and found this medaillon:
photograph by I, Sailko, distributed under a CC BY-SA 3.0 license.
As you can see the font used is rather simple, so I decided that it would make a lot more sense to go with a renaissance and not a blackletter font (which I wanted to go with first). I found two free fonts I liked:
As for the numbers, I decided to go with the design from the clock of the St Michael-at-Plea church, Norwich, UK.
photograph by Leo Reynolds, distributed under a CC BY-NC-SA 2.0 license.
As you can see in the picture attached to this step, I ended up designing a few different versions of the clock. I uploaded the final version I used to this step as an inkscape file so you can print or plot it in any size. You can download inkscape here.
Step 3: Modifying the Clock
First I tried to simply spray paint the clock face black. Sadly that didn't work very well since the numbers shown through and the paper started to curl. So for the next version I decided to remove the paper, as shown in the pictures.
Afterwards I used a thin sheet of black plastic and spray painted it as well as the clock black to make sure that everything has the same colour.
I used my plotter to cut the number out of vinyl foil and glued them to the black plastic circle.
You can of course simply print the design onto a thick sheet of paper, should you not have access to a plotter.
Now all that was left to do is to glue the circle to the clock. Double sided tape worked best to do so for me. Make sure to position the clock face right since your might have a hole to hang it and you don't want the twelve to be at the bottom.
Step 4: Modifying the Clock Mechanism
I used the loudest clock mechanism I could find, which I took from another cheap clock. The brand is called "Sangtai 5168".
Start by opening the clock mechanism. You can either use a screw driver or your nails, be careful and make sure that the tabs don't break or the gears fall out. Once you pull the lid off, make sure to hold the clock mechanism up right, as shown in third picture.
Place the clock onto a tape roll or something else with a hole in middle, to prevent the gears form moving out of place.
I suggest taking pictures of your clock mechanism, since there are many different ones and the pictures I am showing here might look different. Even though the gears might be different there is always a small circuit board with a spool, that you will have to get to.
Solder two wires to the spool connections, as shown in the fifth picture.
Cut a small hole into the plastic case, place the wires through it and reassemble the mechanism.
Step 5: The Electronics
The electric circuit is an SMD adaption from the opensource version by Simon Inns and also uses a PIC12F683 IC for controlling the clock pulses.
The board you can see in the images was produced by PCBWay. I payed $5 for 10 boards, which I decided was a way better options than producing them myself, since etching/drilling/tinning the boards is always quite a time consuming process.
You can find the corresponding EAGLE files attached to this step.
After soldering in all components you just have to connect a PIC programming kit to the programming port (the six pins in a row) and upload the corresponding firmware. In my case I did not really like the huge randomness that is present in the original firmware as this deviates somewhat from the original in the books (putting people off by as they are never sure if the clock is wrong or their perception of time is). This firmware uploaded to this step introduces only few pseudo-random ticks per minute and works most of the time as a normal clock. I used MPLAB X for compiling and uploading the firmware.
Step 6: Assembly
Once you have finished your board and modified your clock mechanism all that is left to do is to connect them as shown in the picture. The orientation of the two wires going to the clock doesn't matter.
The circuit runs on 3 V so you can simply connect it to two AA batteries.
Step 7: Bonus: 3D Printing the Clock
If you can't find a clock you like, but have access to a 3D printer, you might wand to consider printing it:
The first version of the clock I made was 3D printed, so I decided to show you how I made it.
Since I wanted the clock to be bigger than what my printer could handle I decided to divide it into three parts. I used the "fast print"-setting on my Ultimaker, because due to the assembly later on I had to smooth the parts anyway.
As you can see I designed small slots and placed nuts into it so that I could screw the glas and back plate in place (which I cut with a laser cutter).
After that I glued them together and held everything in place with a tension belt.