24 hours a day

Applications for iPad and iPhone often make use of the 24 hour dial, mainly because it’s a much simpler interface to the daily routine, showing the entire day at a glance, and avoiding the inevitable confusion between AM and PM.


Rove is a simple iPhone app that tracks your movements unobtrusively, in the background, and records them, together with any notes and photographs that you take as you go. Billed as private journalling or life-logging, Rove shows your current day (only the current day at present) on a 24 hour dial:



Owaves is, according to the developer, “the world’s first wellness planner”:

Owaves makes it easy to plan health and wellness goals into your day. Colorful and vibrant, with a novel 24-hour clock, the planner is fun to use and lets you see your day in a whole new way. Oriented to sunrise and sunset, Owaves guides you to a balanced lifestyle and healthy circadian rhythm.

Eastern and Western health experts agree there are five main ingredients for a long and healthy life:




-Mindfulness, Meditation, Yoga, Managing Stress

Love and Social

Owaves is the only day planner in the world designed to let you prioritize these activities alongside work, play and miscellaneous errands.

The planner incorporates input from thought leaders in chronobiology, mindfulness, and professional sports.

It’s Visual. It’s Fun. And it’s Easy-to-use.

owaves health clock

The developer explains:

The clock is oriented with sunrise at traditional 12 o’clock position. Sunrise and sunset are prominently featured and localized based on the user’s location. There’s arguably an epidemic of circadian rhythm disorders going on post-rapid spread of artificial light, so this gentle “nudge” is meant to remind the user that sunrise is the beginning of the day.

– menu of activities focuses on 5 key aspects of preventive health as per the American College of Preventive Medicine and American College of Lifestyle Medicine: exercise, sleep, nutrition, stress management, and love/social

The future plan is to integrate wearable device data to create a feedback loop for wellness and health applications.

Through the lens of wellness and health, the 5 main activities featured – Exercise, Sleep, Nutrition, Relax (i.e. managing stress) and Love/Social (i.e. spending time with loved ones) – are THE activities of interest. Considered the new “lifestyle vital signs” by the American College of Preventive Medicine and the American College of Lifestyle Medicine, since they are more prognostic of chances for future morbidity and mortality for today’s generation than the vital signs of the past (i.e. HR, BP, RR, etc.). I.e. they are more helpful in assessing one’s chances of obtaining a chronic disease like: diabetes, heart disease, high blood pressure, obesity, metabolic syndrome, depression, anxiety, osteoporosis, …

The next version will include: Weekly and Monthly views, Social Sharing Options, a Brief Tutorial and a bit more… And of course, as mentioned, calendar integration and circadian rhythm intelligence are on the books as well.

Owaves is promising, and will become much more useful when calendar integration is implemented.

Butterfly Dial

The Butterfly Dial is an ingenious invention designed to combine both the 12 hour and 24 hour dials into a single 12 hour dial.

It’s much easier to see it in action than try to explain it:

butterfly dial

The video can be seen on YouTube.

It’s no substitute for a true 24 hour dial, but it’s a much neater solution than the Cyclos dial, described in the Design page of this site:


The Life-Clock Kickstarter Campaign

Chris Wiegman has set up a Kickstarter campaign to build 24 hour clocks. There’s already an iPhone app, with iPad and Android apps to follow if the campaign is successful.

The basic idea seems to be that you can customize the clock with your activity schedule, around the outside, seeing at a glance how the different activities during the day are organized. This is one of the helpful aspects of the 24 hour dial – we’ve heard from Sylvie about her work in Sweden with the Pajala Klockan.  And the clock designed for Saffron allows you to change the length of the night and day sections.

On the app version, you can change the labelling and colours for the various sectors, or switch between various presets.

For more information about the Life-Clocks project, visit

Train interval indicators

These 24 hour train indicator dials are apparently still to be found in the entrance lobby of the headquarters of the London Underground, at 55 Broadway. They featured in David Heathcote’s TV program looking at London’s 1920s Art Deco heritage, shown recently on on BBC 4.

There’s a separate indicator for each of six main lines running when the building was first opened. It’s possible that one of them is still running today.

Each dial starts at 0600 and runs until 0100, passing through 2400 on the way, and appear to rotate clockwise, past an indicator at the bottom. How they actually indicate the trains is not clear —if anyone knows, please tell us!

Such a modern look wouldn’t be surprising, of course, since Frank Pick had just become managing director of what is now called London Underground. Frank Pick’s preference for the 24 hour time system can be seen in this letter to the London Times, on May 4, 1931:

Sir,– I note that on Wednesday next Lord Newton is to move in the House of Lords for the adoption of the 24-hour clock recommended by the Home Office Committee as far back as 1919. 

To the general inconvenience, we still proceed to reckon time, not by days, but by half-days. This is, perhaps, forced upon our attention most in railway time- tables, for railways run continuously round and round the clock, and in international broadcasting programmes where all times of the day become one time. 

The Underground day, although it has defined limits, is odd, starting about 5 a.m. and closing about 1 a.m., some 20 hours later. Numerous devices of type and symbol are employed for distinguishing anti- and post-meridional time, but they are often uncertain and sometimes clumsy. It would therefore be a gain if the convention of the 24-hour clock, covering the entire day, were commonly adopted so that 2.30 a.m. would be plain 2.30 and 2.30 p.m. would become 14.30.  

On the Underground Railways we should be prepared to make the change. Certainly the transit of the sun across the meridian has no visible significance underground.
For one, however, to change is only a gesture, and has its awkward reactions. If all who use time for time-tables were to change, then we should have rationalized one further detail of living. 

Yours faithfully, 


55, Broadway, Westminster, S.W.1

and again on 7 December 1933:

Sir,–I note the Astronomer Royal’s letter in The Times of December 2. 

As it happens, the London Passenger Transport Board has to consider the reprinting of its time-tables for its railway and coach services, and the problem of distinguishing between a.m. and p.m. once more arises. It seems strange that there should be any reluctance to adopt a proposal which has been found necessary in all those spheres of activity in which exactitude is essential. 

That there is a need for a solution of the problem must be apparent to anyone who studies time-tables. For it will be found that all kinds of typographical devices are used in an attempt to avoid any confusion between a.m. times and p.m. times. 

I therefore once more urge that we should now adopt a common practice in this matter. Once it is adopted and made a common practice,no more, I am sure, will be heard in criticism of it. 

Yours faithfully,  


55, Broadway, Westminster, S.W. 1

More details of how Britain tried and failed to adopt the 24 hour clock can be found in the ebook: Counting Time.

Emerald Chronometer

Emerald Chronometer HD is a watch simulator app for the iPad made by Emerald Sequoia. (There’s an iPhone version too, called Emerald Chronometer.) The app consists of fifteen watches (named after cities) created in software, with each watch offering different features on its front and rear faces.
At first glance, you might imagine that there’s not much point to simulating watches on an iPad. After all, doesn’t the iPad tell the time perfectly well, even if it doesn’t come with a built-in clock app, like its smaller brother?
But you’d be wrong: the developers of Emerald Chronometer have blended the legacy of centuries of fine watch-making craftsmanship with the latest interactive touch-screen technology to build a digital playground that lets you investigate the worlds of time-keeping and astronomy with your fingertips.
Each ‘watch’ offers a different approach to time. Rather than copy existing models, the designers have created new, imaginary watches that blend features from traditional time-pieces with features that you could expect to find only on an extremely expensive watch, or a powerful computer.
For example, the Vienna offers a traditional 24-hour display (the rear face offers a version with 12 at the top). The app synchronizes with the NTP protocol over the internet, which means that these watches almost certainly keep time more accurately than the iPad itself. I’ve clicked on the Time Synch button which pops up a display showing how far adrift my iPad is. The white, black, and grey bands on this and other watches show the current lengths of day, night, and moonlight periods.
Where the Vienna is simple, the Geneva is complex. The front face shows the time as fully as possible, including years and leap years (recognizing both Julian and Greogrian calendars), sun and moon rising and setting times, and moon phase and age. The rear face shows local apparent sidereal time on a 24-hour dial, the zodiac, equinoxes, and solstices, the positions of the lunar ascending and descending nodes – even whether there’s an eclipse soon.
But the real magic of this app is revealed when you ‘pull out’ (or tap) the crown for the current watch. The watch stops, and you can then pull and push the hands and indicators around the dial to your heart’s content. Watchmakers will find it unbearably painful to look at as you pull the hour and minute hands into different positions, or scroll the indicator dials up and down through the years with the flick of a finger. If, as you’re moving through time, there’s the possibility of an solar or lunar eclipse, the eclipse indicator at the top of the Geneva will let you know.
The Alexandria watch, named for Ptolemy’s home town, displays the time using a geocentric display; the Firenze watch, named for Galileo’s sometime home, is an orrery – a sun-centered display of the solar system. And in each case, you can drag the planets around to see how they move in space as you travel through time.
The Miami watch shows the rise, transit, and set times of all the planets (and the Sun and Moon), with a single hand on a 24-hour dial, and their current azimuth and altitude.
The Terra watch specializes in time zones: the front shows your chosen zone at the top, with a 24-hour ring to help you read off the time in other cities. Again, being able to move the rings round makes it easy to explore time zones and time differences. The rear face provides four dials for your favourite cities.

On the Olympia, you’ll find a stopwatch; on the Thebes, a countdown timer; and on the Istanbul, an alarm, which chimes like a traditional watch.
If you have an iPad (or an iPhone), this app is a cool and clever addition to your library, and a pleasant way to spend (and learn about) time.