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"The Black-Standard"
A new standard for easy to read binary clocks
Roman Black - 14 March 2007 - web Feb 2008 - web pics fixed Jan 2009

ALSO click HERE to download a Black-Standard binary clock for Windows!

ALSO click HERE to build your own PIC based binary clock kit!

What is it?

This is a "standard" for binary clocks. The standard covers the shape of the digit segments, the position of the segments, and the purpose of the segments.

Theory - The Black-Standard using shaped segments

Binary clocks are becoming a popular curio. As a technical person I also like the beautiful simplicity of a binary display. For example, a traditional 00:00 clock with 7 segment displays requires up to 29 segments, but a pure binary clock (like this standard) requires only 10 segments (and can be driven directly from a cheap 18-pin PIC).

The few binary clocks on the market are over complicated and not very attractive or easy to read. I set out to design a standard that met the following specs;

  • Always readable in the dark - requires no indicators
  • Always 1 segment or more are lit
  • Perfect readability even if only 1 segment is lit
  • Single colour segments
  • Integration with human needs - "Is it half-past yet?"
  • No more than 4 bits in any field
  • Pure binary, no messy BCD
  • Visually attractive
  • As easy to read as possible while satisfying above specs

    One of my main requirements was to remove the need for "indicators". Other binary clocks need indicators to be readable. ie in a dark room a binary clock that displays "01000" or "00001" is only readable as "1". With the room lighting on the "0" bits are required as indicators to visually decode the entire binary field.

    In this standard the hours field always has at least 1 segment lit. Hours are displayed from binary 1 to 12, never binary 0. Therefore it becomes the reference for the entire display and is placed in the centre. Each segment within the hours field is a different shape and each is individually recognisable both for the bit it is, and also for the position it has within the clock face. The design of the shapes allows for easy visual "centering" of the entire face. See below.

    My other requirement of interfacing with human needs, led to the design of a quarter hour field, of 2 binary bits. This is instantly recognisable as "quarter past", "half past" and "three quarter past" and for many human clock needs the visual display of quarters can be as much time information you need to know at that point. See below.

    As the Black-Standard is based largely on simplicity, in its purest form the standard would only require the 6 segments shown above and creates a clock that displays as hours and quarter hours. It would be a valid Black-Standard binary clock but obviously limited to a resolution of a quarter hour.

    But for most uses, the display of sub-quarter hours or "extra minutes" is handy either for visually decoding as an exact minute, or visually estimating as "this quarter is almost over". See below.

    This is quite practical with the extra minutes field, as the leftmost segment represents 8 minutes which is about half of a quarter hour. I have found the human brain very quickly adapts to this method of reading the clock, and you soon find a that with even a very quick glance you can see the relative time within that quarter, in a similar way to the way a traditional analog clock dial is easy to read.

    I considered 3 standards for the extra minutes;
  • 4bit binary - range 0-14 - in actual minutes
  • 4bit binary - range 0-15 - in perfect binary division of quarter (0.9375 minute units)
  • left-right bargraph - any length (shows time progression through that quarter)

    For the primary standard I settled on the first option. This is because it does 2 things; easily showing the rough progression through the quarter, and the ability to see actual minutes when required. This primary standard is shown in most of the clock faces seen on this page.

    Here are some examples of the other sub-quarter options within the standard. See below.

    A standard of dimensioning is needed, I have found these dimension specs to be very workable (in terms of recognition) and reasonably attractive. The specs are "fuzzy" meaning they are a rough guideline to be adjusted as needed to give the greatest readability or the nicest attractiveness. See below.

    Note the hours and quarter hours segments have a similar area, but the extra minutes segments are much smaller. The similar large area of the lit segments gives a similar perceived brightness and impact to the eye. Likewise, the smaller area of the extra minutes gives them less impact to the eye so at first glance the eye sees a simplified display of just the hours and quarters, with the minutes being available on further inspection. See below.

    Notice above how the shapes of the segments encourage the eye to always see the centre of the clock face, either by the vertical line or by the symmetry of the outside segments.

    The Black-Standard using just dots

    For convenience of construction, I also adapted the Black-Standard for use with simple dots. This allows use of standard display components like normal LEDs, large scale LEDs, light bulbs, and industrial electro-mechanical display elements.

    After a lot of thought and testing I settled on the 10-segment 16-dot standard seen below.

    Here is the rough dimensioning seen below.

    I have found these spacings of the dots give good readability (provided the user is already familiar with the standard). The dot standard maintains 100% reliable reading of the clock even in darkness. See below.

    The Black-Standard using a 5x7 LED display

    Here is an adaptation fo the standard for use with a standard 5x7 dot matrix ascii display, many common brands like Hewlett Packard, Kingbright etc.

    It wasn't too hard to adapt the standard to this format display. The main problem was making the middle 2 hours segments individually identifiable. That was solved by sharing the centre dot between both these 2 segments. This distinguishes them from each other, and also from the outer 2 hours segments.

    These dot displays make a very neat little binary clock, and the standard adapts well enough to 5x7 to still maintain 100% readability in the dark without indicators.

    The driver circuit only needs 4x7 drivers, would suit 11 PIC pins and 7 resistors, so it is still very compatible with any cheap 18-pin PIC.

    - end -

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