I would like to make such clock:enter image description here

  • It should be composed of several big squared dots
  • If you check, there is no holes, I guess it's only a fine fake wood that is glued above
  • It should have a minimum resolution of 27x7

I can see how to do the wood part, how to the dev part, but I don't see how to have the good number of space/led behind?

I tought of severals things:

  • Multiple leds, but I don't see how to have 189 Leds bounds to a Rpi
  • A led matrix but LEDs are too close from each others

Can you see another solution?


Perhaps: Use the type of leds from an led strip (with integrated controller - ws2801 or something similar). You would have them chained together in series and send updated frames to them in a serial fashion using a library like PixelPi

I'm thinking of an led strip a bit like the one used in this: http://tobiscorner.floery.net/rgb-pixel-clock-part-3/

Alternatively: Your clock looks like it mimics the old 7 segment displays of the past - you could group the leds into segments and add drive circuitry (a mosfet?) for each segment. The traditional way that 7 segment displays are driven uses 7 lines for the segments and then another line for selecting each digit. The digits are then driven one by one very quickly so that persistence of vision makes them all appear to be on. Now you're only using 7 + 6 gpio lines from the pi. A bit like this: https://projects.drogon.net/7-segment-led-display-for-the-raspberry-pi/

  • This is viable and a nice way of doing things. Hell, if you used addressable LEDs then you'd only need... 3 pins I think? Feb 1 '16 at 22:42

I would probably consider six 7-segment LED displays controlled by I2C as the simplest option for the Pi.

The 7-segment display would be limited in the character set (just like old LED calculators) but the characters would be instantly recognisable for a clock.

  • The 7 segment doesn't have the rendering at all that I want, sorry
    – J4N
    Feb 2 '16 at 6:46

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