This clock was developed for the exhibition "Invisible Powers - Between Art and science" which was held at the 'Bloomfield Science Museum' in Jerusalem at the 22 of march.
 |
| Front View |
 |
| Rear View |
Name: Analog clock in a digital world
Description: A pendulum wooden clock, that displays the time in a digital form.
How it works (in short): a wooden pendulum system signals to an optical sensor. This sensor operates a small motor which drives a transmission gear train, which operates a digital display.
The Mechanism
A detailed description:
The object is composed of three main components:
1. Minutes Counter
 |
| Optical sensor on the Escapement wheel |
How it works: Basically it is a Wooden pendulum clock without the dials.
Materials: Plywood [cut by CNC machine], Brass rods, stainless steel weight
How it was made: The plywood gears and frame were cut in CNC machine, using 3mm cutter.
Credits: The gear train itself and the frame design is based on the 'Primus' clock, designed by David Atkinson, with some changes (plans can be bought here)
2. Transmission Gear Train
this part controls the display. stainless steel bearing-balls are held in perspex wheels, and when in the right position they close an electric circuit and turn on the led strip which lights the suitable display-segment (made from 3 layers of sanded perspex).
How it works:
There are four SSD (seven-segment-display) digits in the clock, marked from 1 to 4, when 1 is the first digit from the right.
There are four gear compounds, marked from A to D, when A is the first gear from the right.
In order to show the time correctly:
digit #1 needs the ability to show digits 0,1,2,3,4,5,6,7,8,9 (ten options)
digit #2 need to shows digits 0-5 (six options)
digit #3 needs to show 0-9 (ten options)
and digit #4 shows 0 or 1 (two options), Since it is a 12 hrs display,
gear A controls digit #1
gear B controls digit #2
gear C controls digit 3 AND 4
gear D controls the AM/PM display.
the input comes from the attached electric motor, which turns one turn every minute (speed of about 12 rpm).
the electric motor turns gear-A 1/10 of a turn.
aftergear-A turns a full cycle,
it turns gear-B 1/6 of a turn
After gear-B turns a full cycle,
it turns gear-C a 1/12 of a turn
and after gear-C turns a full cycle,
it turns Gear-D 1/6 of a cycle.
the mechanism that drives this system is an adaptation of Odometer mechanism. this mechanism is the one that you can see in every car, measuring the total mileage/kilometer that the car drove. the mechanism in my clock, though, is much more complex, since odometer drives each digit by the ratio of 1 to 10, while in this clock the ratio is changed every digits, like I explained above. the mechanism was built from MDF, and is 10 times bigger then the average odometer mechanism.
Here is a video that shows how the transmission system works. for testing purposes, the electric motor is working continually. on the real clock it is running one cycle every one full minute.
the gear compounds are an array of acrylic circles, connected with threaded rods and with precise spacers. this array can hold stainless steel balls in a specific place, which allows enough room to move but not to fall out. when a compound turns, the balls at the bottom lay on a 2mm threaded rod, and by that it closes an electric circuit and turns on the relevant segment.
There are four SSD (seven-segment-display) digits in the clock, marked from 1 to 4, when 1 is the first digit from the right.
There are four gear compounds, marked from A to D, when A is the first gear from the right.
In order to show the time correctly:
digit #1 needs the ability to show digits 0,1,2,3,4,5,6,7,8,9 (ten options)
digit #2 need to shows digits 0-5 (six options)
digit #3 needs to show 0-9 (ten options)
and digit #4 shows 0 or 1 (two options), Since it is a 12 hrs display,
gear A controls digit #1
gear B controls digit #2
gear C controls digit 3 AND 4
gear D controls the AM/PM display.
the input comes from the attached electric motor, which turns one turn every minute (speed of about 12 rpm).
the electric motor turns gear-A 1/10 of a turn.
aftergear-A turns a full cycle,
it turns gear-B 1/6 of a turn
After gear-B turns a full cycle,
it turns gear-C a 1/12 of a turn
and after gear-C turns a full cycle,
it turns Gear-D 1/6 of a cycle.
 |
| The odometer gears can be seen between the acrylic circles |
Here is a video that shows how the transmission system works. for testing purposes, the electric motor is working continually. on the real clock it is running one cycle every one full minute.
 |
| An early version of the acrylic compound |
the gear compounds are an array of acrylic circles, connected with threaded rods and with precise spacers. this array can hold stainless steel balls in a specific place, which allows enough room to move but not to fall out. when a compound turns, the balls at the bottom lay on a 2mm threaded rod, and by that it closes an electric circuit and turns on the relevant segment.
 |
| Rear View |
How it was made: All gears were designed with the program Gear Template Generator, made by the very talented Mattias Wandels. the gears, made from MDF, were cut by a laser machine after exporting the gears to DXF format.
Materials: 4 mm Perspex, 6mm MDF, Stainless steel bearing balls (12.6 mm), 6mm threaded rods, sleeve nuts
3. Display
A 4-digit seven segment display,
Materials: 6mm MDF, 3 layers 4mm sanded perspex, 28 red smd led stripes,
Notes:
the motivation for relying on metal balls to close an electric circuit was based on the understanding that the pressure should be reduced to minimum. any kind of switch with a spring would require force to press on it (whether it NC or NO) and since that one turn of the gear can turn almost 28 switches on (at worst case scenario, when it moves from 11:59 to 12:00), the friction would be too much for a small motor to carry.
The disadvantage is that this kind of contact is very delicate and fragile, and even the slightest shock can cause the ball to move and to loose the contact, and therefor to disrupt the digital display. The clock needs more work in order to improve its movement. I belive i will find the time to omprove it, and this wont be the final configuration.
The product was designed and built by Elyasaf Shweka, Industrial designer, currently works at A contracting company in Jerusalem, And with the intensive help of Nir Shweka, an architecture student.
The next video shows time changing on clock
The Process:
Trying to invent a new mechanism is not as easy as it seems.
In this photo you can see all the parts that are being made by laser cutting and by CNC. All these parts are in the clock you see above. its not all the parts of the clock, but most of them:
Here are some of the pieces i made during the process (3 last months) and I didn't use at the end. they are all not useful now, but every part here had its job to advance me toward the goal. It is recommended to englare the picture....
I would love to hear your comments, tips, improvements etc. about this project. feel free to comment below (no sign-up needed) or to email me at shwekwek@gmail.com
More images of the project can be viewed here:
You are also welcome to check out another clock that I did to the same exhibition, similar concept with a different approach. HERE
 |
| Analog Clock in a Digital World |
You are also welcome to check out another clock that I did to the same exhibition, similar concept with a different approach. HERE
| Control Panel |
