The “Quinhora” LED Number base-5 Clock kit

(Released 27th August 2008)


You may have seen “Binary” clocks that show the time using columns of LEDs.
Now you can build this interesting base-5 clock that shows the time using multiples of “Fives” and “Ones”
It may appear to be a just a random pattern of LEDs at first. But once you understand how it works, it really is very easy to use.

The time is shown using the number Base-5 (Quinary) format as shown below.


The Base-5 number format was used for a public clock in 1975.
It was commissioned by the Berlin Senate to be installed on a main street called the Kurfürstendamm.

Invented by Dieter Binninger, it used long-life light bulbs to show the time.
High running costs resulted in it being shut-down in 1995.
In 1996 it was renovated and moved to the entrance of a Berlin shopping centre where it is still working.
An East-German table-top replica model using LEDs was manufactured until the late 1990s.

In Summer 1998 “Elektor” magazine published a construction project using a PIC16C54 and then in Early 2007 an article called “Berlin Clock re-make”.
Their 2007 design is an SPI display interface and does require a separate micro-controller system to drive it.

The “QuinHora” design uses the same basic display format as the Berlin clock, except for an RGB LED at the base of the display for showing seconds activity etc.
The 15,30,45 minute LEDs are slightly displaced to make it easier to read the minutes.
It also has many user-configurable software features.


  • The core of the clock is a Microchip PIC18F1330 8-bit CMOS microcontroller IC.
  • It is programmed entirely in assembly language code for high performance.
  • Timing is provided by a battery backed Dallas/Maxim DS1307 RTC “Real Time Clock”chip.
  • Time & date is retained during power-off. The timing accuracy can be finely adjusted in the clock software.
  • It incorporates an alarm clock with selectable alarm sounds/tunes, adjustable volume and snooze timer.
  • The display uses high quality “Super-bright” oval,tinted wide-angle LEDs for ease of viewing and has five brightness settings.
  • All components are high quality through-hole types for easier assembly.
  • All clock option settings are adjusted using three push-buttons and are retained in the controller EEPROM memory during power-off.
  • It is very configurable with over 20 option settings –
  • 24 or 12 Hour time display with PM indication
  • Automatic DST “Daylight Saving Time” adjustment for UK/Europe and US zones.
  • Display brightness can be automatically dimmed or turn-off between set times, ideal for night time use.
  • There is a pulsing RGB (Multi-colour) LED with choices of colours for seconds activity indication.
  • The LEDs can be set to fade on/off (similar to incandescent light bulbs).
  • Incorporates a date display option and automatic leap year compensation.
  • There are several display special effects which can be configured to run at various intervals.
  • Chimes options, including sounding the hours.
  • If you are a geek who wants even more features, there are two outputs ready for you to optionally add your own circuits to, such as auxiliary alarm indications, or to flash more LEDs etc.
  • It is powered from 9 Volts DC, so can be used worldwide (with appropriate mains adapter)
  • Configuration can be reset back to defaults if you wish to.


  • Power: A 9 Volts DC power adapter (wall-wart) (Regulated or Unregulated) is required.
  • Power consumption: Less than 1 Watt (at 9V DC input).
  • Dimensions: 80mm X 80mm (3.15” X 3.15”)
  • Timekeeping Accuracy: Un-adjusted accuracy +/- 1.7 seconds per day)
  • Weight: (no case):Approx 20 grams (0.044 pounds)

You can download the user manual here:

Quinhora Clock kit User manual

Kit Availability – SOLD OUT!