Picture of Lunchtime Clock
Have you ever wished lunchtime were longer, but didn't know where to find those few extra minutes? Well, wish no longer!

Thanks to great in advances in clock technology, I present to you a clock that speeds up 20% every day at 11:00 and slows down 20% every day at 11:48, giving you an extra twelve minutes of lunch to enjoy. Twelve minutes may not seem like a lot but, to put it into perspective, this is a full additional hour of lunchtime gained every week.

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Step 1: Go get stuff

Picture of Go get stuff
You will need:

(x1) Standard wall clock
(x1) Adafruit DS1307 Real Time Clock Kit
(x1) Arduino (w/ATMEGA168 DIP chip)
(x1) Extra ATMEGA168 chip with Arduino bootloader installed (see last step)
(x2) BC547 PNP transistors
(x2) BC557 NPN transistors
(x1) 28 pin socket
(x2) 22pF capacitors
(x1) 16mhz crystal
(x1) 1K resistor
(x1) 7805 regulator
(x1) 4 pin socket
(x1) 9V battery and connector

Step 2: Remove the movement

Picture of Remove the movement
Remove the clock movement from the clock body. This will require removing the front glass face from the clock as well as the clock's hands. Be gentle as not to break anything. You will have to reassemble everything later.
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If I ever see one of my employee use this clock, he's fired immediately !

(now, I wouldn't mind having the same in my own office !!!!… ;) ;)
RodCastler2 years ago
hi! nice project. Why are you using 50% duty cicles in your tutnturnturn function instead of digitalwrite(pin,on) ?
randofo (author)  RodCastler2 years ago
It is not a DC motor. It is a single coil stepper motor. Power it on will make it move one step and then stop.
giangtoxom2 years ago
Hi Randofo, your project is great !!
I'm going to make it for all my radio station wall clock (just to sync real time to them)
If so, how is write code "lunchtime_clock" cause I don't need it speed up or slow down, just run the real time load from RTC chip ?
Thanks in advance !
DerekK192 years ago
I love this idea. Simple, elegant and soo cool. I'm tempted to go the whole hog though and have a "work time" clock that speeds up at 8am and slows down again at 5pm. Of course the party poopers will say that you have to adjust all the office computer clocks and everyone's watches, but for novelty value this is a real winner. I promise I will build one
larryb643 years ago
I don't care what anyone else says... It's creative and genius...
and did anyone else get the Douglas Adams reference below... NICE!!!
wellebh3 years ago
This is pure genius.
rustygray4 years ago
Naysayers be doomed. This is an interesting concept of relativity and time.

If you think 30 seconds is a short time, try holding your hand 2 inches over a candle for 30 seconds, then be allowed only 30 seconds for a bathroom break to realize how fast it goes by.

Time is relative, and if the lunch break can appear longer, then your mind tells you it is.

Fabulous idea and could be fun for pranks and practical jokes.
Time is an illusion, lunchtime double so :p
42 ;-)
Is that a Douglas Adams quote? true!
PACW rustygray4 years ago
True enough - but your example was a bit G. G. Libbian (Libbyesque?) for my comfort!

Time is fleeting; madness takes its toll...
Isn't it funny to see how all these people react to this ible?

Some clearly don't get it, some think you can accomplish the same outcome by setting the clock back 12 minutes, some people talk about the time stamp on a time card machine, some people talk about small businesses v. whatever else there is, some think they'll lose money, some want to discuss the programming.

But I guess I'll join the majority and say VERY IMPRESSIVE. GOOD JOB.
I agree. The ible doesn't proscribe where you use this. If you want to try "to get away" with something at work, and you think you can, and feel that's a good thing to try, then great, have fun with it.

My lunch room at work doesn't have a clock, nor does anyone care when I eat lunch (or when I show up or go home for that matter) but I didn't think to use this at work when I saw it. As they say: "everything is relative".

For that matter, the ible includes source code for noon hour but there's nothing stopping you from adapting that for other uses. I cannot think of any at the moment, but I'm definitely bookmarking this just in case it might come in handy adding to another project.

However, I like weird clocks, and this one is very subtle that the fun in it seems to be "how long would it take anyone to notice", plus the sheer enjoyment of actually getting it working (which some people seem to miss on this website as well).
PACW4 years ago
Very very nice! I must admit the electronics is beyond me but I like anything that reminds people just how arbitrary time is! Be sure to post again when you start selling these, I don't need a longer lunch hour but I like bendy timepieces.
Jollyrgr4 years ago
This works if it is the ONLY clock in the building where you work. Thus it must be a VERY small business. At my location we have clocks on:

*Cell phones
*Time clocks

Likely after a day or two someone will catch on this clock has a problem and go to replace the battery or replace the clock.
randofo (author)  Jollyrgr4 years ago
We have about 20 people... I see how well they clean the shared kitchen... The likelihood of them even thinking about changing a clock battery is about nil. Come to think of it, the last clock sat with a dead battery for months.

Anyhow, it is only at most incorrect visually 12 minutes. Most of the time it is only off a matter of a few minutes. I feel that this discrepancy is not enough for most people to notice or care. Even if they did, the fact that the clock is correct about 90% of the time would probably dissuade anyone from changing it. I'm guessing it would take most people a long while to figure out what is going on in spite of the abundance of alternative clocks.

Clearly this won't work in every single work environment and I don't believe I made that claim, but I think you are wrong that this will work in none.
Honus4 years ago
Awesome. I bet you could sell boatloads of them on ThinkGeek.
eoutlaw Honus4 years ago
I was thinking exactly the same! This is a great idea and execution. You should definitely pitch this to Randofo, prepare to make millions, haha.
agis684 years ago
well...i don't get it!!!, Maybe cause i live in a democratic country where anyone office staff can choice by self the right time and last of his lunchtime or for more breaks. Is enough to report his employer that he needs some minutes to eat something.
Teachers can't do that but they (we) have one free hour for every 4 hours of teaching. Bus drivers also have their breaks but generally every staff can break in a spirit of understanding of freedom and human rights and maybe some times health problems. We (greeks) invented democracy and we apply it. So simple. Only in Army forces have restricted Lunchtime hour, for the rest people its free!!!
so basicly, the special clock speeds up to get to lunch time 12minutes early, then, during the lunch hour, it slows down at the right speed to line up with the proper time.
cprocjr4 years ago
Amazing! I just need to figure out how to change all the clocks in the building so that no one catches on.
JohnJY cprocjr4 years ago
Or just set back every clock in the building 12 minutes.
cprocjr JohnJY4 years ago
1. That is really easy to catch because it is always wrong. People have watches/computers.

2. That doesn't actually extend lunch, it just shifts it forward.
pcgirl cprocjr4 years ago
No. It adds 12 minutes to your lunch break. Ignore how the clock works for a minute and just think of it , as if someone has turned the clock forward 12 minutes when you weren't looking. Then when you go to lunch, they turn it back to the normal time. You get an extra 12 minutes. The clock is just being that sneaky person, but electronically. :) I think it rocks!
cprocjr pcgirl4 years ago
I was replying to 94. The clock in the instructable actually does extend the time.
JohnJY cprocjr4 years ago
Yeah, whoops. Haha. Anyway, the concept is amazing.
pcgirl4 years ago
I have been trying to think of a person who can do this for me.. Absolutely love it. :D
Well then I would lose $1.73 for those 12 minutes I am spending not getting paid.
Well, yes, if your boss doesn't use that particular clock to pay you.
Unless I am completely misunderstanding this.
Give it some more thought, if the hour between 11 and "12" is faster by twelve mins, it will say it is "12" at 11:48 - when you write your timecard with your lunch break on it, the clock will say 12 - 1 when in actual fact it is 11:48 - 1..... because it looks like a standard hour, nobody will be the wiser
But, that's now how most time clocks that actually stamp a card work. They are normally hooked to a central server where a manager, supervisor, or corporation can adjust it for accuracy and security.

This will work for small shops where a manager is always relying on a single clock for timing... otherwise it's just fun to have around.
Being the majority of people work for small businesses (in the USA) and do not punch their time in, it would be relevant for most of us.
Per the Small Business Administration (SBA). Small enterprises account for 52 percent of all U.S. workers.
sumatra4 years ago
Your Instructable would be a lot stronger if you explained your circuit and code. How did you arrive at the circuit and the values for the AnalogWrites? Do you really need the transistors? The ATMega can source/sink 40ma, and I'd be surprised if the clock coil needed anywhere close to that amount of current.
randofo (author)  sumatra4 years ago
The value was arrived at because 255 was too much and 100 was not enough. I meant to stick in 127, but put in 124 for some reason and that seems to work fine.

I added an H-bridge because the motor is a single coil stepper and needs to be powered in phase (i.e. you need to reverse the polarity).

TurnTurnTurn(x) is a variable for pausing between steps of the motor, whereas x is the delay time. 1000 is equivalent to one second.

Every day at 11:00, the clock goes into a routine that slows down 80% for 3,600 rotations and then speeds up to 120% for 3,600 rotations and then resumes normal operation.
The H-bridge only amplifies the signal it receives from the control pins it's connected to. Polarity stays the same, so I do believe it would work without the H-bridge, just connect the pins directly to the stepper coil... :)
randofo (author)  imarcianoloco4 years ago

This is flip-flopping it:

analogWrite(clockpin, 0);
analogWrite(clockpin1, 124);

analogWrite(clockpin, 124);
analogWrite(clockpin1, 0);

Michael_oz4 years ago
Fantastic concept, great 'ible.

Perhaps two buttons one to pause one to advance X steps, will allow the time to be adjusted?
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