Monthly Archives: May 2015

Two-Four Timepiece – 24 hour clock

Introducing the latest clock from WoodUino – The Two-Four Timepiece 24 hour analogue clock. The Two-Four Timepiece shows a complete day at a time, and marks out time with an hour hand, minute circles and a gently pulsing seconds marker. Sunrise and sunset times are displayed and the display’s colour scheme changes between daytime and nighttime.


Two-Four Timepiece at 10:29PM showing the nighttime colour scheme


Two-Four Timepiece at 8:37AM showing (not very clearly) the daylight colour scheme

The Two-Four Timepiece display is built using a total of 89 addressable LEDs arranged in strips that radiate from a central point. The strips are adhered to a perforated PCB substrate cut into a squared-base circle shape. The LED strip is controlled by a discrete Arduino UNO and a battery-backed up real-time clock that keeps accurate local time. Sunrise and sunset times are determined using the user’s location (longitude and latitude) and GMT offset (using the DST algorithms previously described) using the sundata.h library, as used in the Graphic LCD Analogue Clock and SolarTracer.

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SolarTracer – Solar Azimuth & Elevation

Ideas sometimes come from surprising places. This weekend we hosted some of Sian’s (my daughter) friends, a couple of whom were interested in my obsession with time and making clocks. Looking at my Graphic LCD Analogue Clock one puzzled over solar azimuth and elevation. As I described the sun’s trajectory across the sky an interesting way to demonstrate this movement came to mind and voila, the SolarTracer, an indoor sundial. From the perspective of someone at the centre of the base, the SolarTracer tracks the position of the sun – its azimuth (East to West) and its elevation to the horizon – in real-time thoughout the day.

Solar Tracer displaying the sun's azimuth and elevation

SolarTracer displaying the sun’s azimuth and elevation. In this image, taken around solar noon, the azimuth was 183 degrees (S) and the elevation was 65 degrees from the horizontal. North is to the right. You can see the shadow cast by the illuminated LED that represents the sun’s position in the sky.

UPDATE [150528]:  I made a second SolarTracer to move the azimuth point of rotation to the centre of the base. The azimuth is controlled by a servo motor that moves from East (90º) to West  (270º) over the course of the day. The sun’s elevation is displayed using a strip of 15 LEDs arranged on the inside of an arc that spans from 0º – 90º to the horizontal.

SolarTracer: second build

SolarTracer: SECOND BUILD using a servo motor for azimuth and a strip of 15 LEDs on a quarter circle for elevation

Apart from showing real time solar position, the SolarTracer provides a useful tool to describe the passage of the sun across the sky and concepts such as solar noon, the summer and winter solstices and spring and fall equinoxes. Eminently hackable and a great conversation piece!

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Graphic LCD Analogue Clock

In a previous article about the 192×64 pixel Graphics LCD Module that I have been playing with, I created a simple analogue clock to exercise some of the text and graphics functions of the fully-featured openGLCD library. I have now added to the functions of the clock to include moon-phases and local times of both sunrise and sunset, all of which are displayed using a combination of bitmaps and text. In addition, I have also added the sun’s elevation, in degrees from the horizontal, and sun’s azimuth, displayed in both polar degrees (North=0°) and text-based cardinal direction.

Analogue Clock with moon phase, sunset, sunrise and sun elevation and azimuth

Analogue Clock with moon phase, sunset, sunrise and sun elevation and azimuth

REVISION [150507]: I have now added the times of moon rise and moon set, and marks on the outer ring of the analogue clock for sun elevation (tick mark) and compass-based azimuth (open circle). However, these additions came at a price – removal of all bitmap icons.

Revision of the Analogue Clock with sun elevation and azimuth, moon phase, and times of sunrise, solar noon, sunset, moon rise and moon set

Revision of the Analogue Clock with sun elevation and azimuth, moon phase and state, and times of sunrise, solar noon, sunset, moon rise and moon set.

REVISION [150517]: Added icons for moon phase (shown as waning crescent) and made minor alterations to clock face. On the clock face, the inner filled circle is the seconds marker, the outer filled circle is the sun’s cardinal azimuth (shown as 101° East) and the tick mark (close to 2 o’clock) is the sun’s elevation to the horizontal (shown as 37°). The revisions to the Arduino code are included below.

Analogue clock with additional moon phase icons

Analogue clock with additional moon phase icons

Take your pick!

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