Picture of Light Spectrum Clock
While time is continuous, most clocks display the time in a discrete way; even 'analogue clocks' often move their hands only once a second. In this instructable, I will show how to build a clock that shows the time continuously by smoothly cycling though the light spectrum. To allow for reading the clock with different levels of precision, we make multiple light cubes: one for which a second will have been passed after each cycle, one for a cycle of a minute, one for hour, one for day and one for a week.

Although it might take some time to learn reading this clock, it certainly is a much more colourful way of finding out the current time!

Step 1: Materials

Picture of Materials
For this light spectrum clock you'll need:
  • Arduino (I used a Nano but most will work; the wiring on at least the Nano, Uno and Duemilanove will be the same)
  • TLC5940 PWM 16 channel (on ebay for around 1,50 pound or sparkfun for 4 pound each)
  • DS1307 Real Time Clock module (sparkfun: 15 dollars) or one with even more precision (this one will be off one minute each week)
  • 5 RGB LEDs, common anode (cheap on ebay if you buy a lot; I bought diffuse LEDs, but I don't think it makes a huge difference)
  • Empty PCB or breadboard, some resistors (see Electronics), dip sockets, wires, etc.
  • Foamboard (white, you won't need a lot) and glue
  • Matte drafting film (diffuse foil; you won't need a lot)
  • Some wood and nails for the frame
  • USB-charger (or power by your computer; the RTC module will keep on counting if you turn off the computer)
If you shop economically, 35 pounds / 55 dollars will certainly be enough for the materials and a beer afterwards.
sarahline3 years ago
What type of resistors did you use?
turiphro (author)  sarahline3 years ago

As mentioned in the text: "R1 is a pull-up resistor and has to be high (10kOhm or more), R2 sets the maximum amount of current for all the LEDs (typically around 2kOhm; test with a LED and power source before you start soldering)."
I think I used 27kOhm for R1 and 1.2kOhm for R2.

You can find more information in the TLC5940 datasheet, both resistors are there because of that chip.
Benadski3 years ago
Very well done!!! :-)

I had the same idea, but never gotten in to it to build one. My design just uses hh:mm:ss and non-fading colors, better for readability, but worse for originality.
nickademuss3 years ago
Very nice, I love new ways to tell time, this would look great with my nixie tube clock!
This is gorgeous. A very original clock. :)