HUD-Like Clock Is A Transparent Time Display

While we have all types of displays these days, there’s something special about those that appear to float in the air. This HUD clock from [Kiwi Bushwalker] is one such example.

The build relies on four 8×8 LED matrixes to display the four digits that make up the time, run by the MAX7219 driver chip. However, the LEDs aren’t viewed directly — that would be too simple. Instead, the matrixes shoot their light up at an angle towards a tilted piece of clear acrylic. This creates a “heads-up display” look where the numbers appear to float in the air.  The clock gets accurate time from an NTP time server over WiFi, thanks to the ESP32 microcontroller that runs the show.

It’s a straightforward clock build in many ways, but we particularly like the use of the heads-up display technique. It’s almost surprising we don’t see these projects more often, for things like car dashboard displays or targeting womp rats in a T-16 landspeeder. If you’ve been whipping up your own HUD projects, don’t hesitate to notify the tipsline!

13 thoughts on “HUD-Like Clock Is A Transparent Time Display

  1. It needs a black roof over the reflector so the LEDs don’t light up the ceiling: 90% of that LED light goes straight up.
    And a black background behind the reflector to get a higher contrast, more readable display that isn’t washed out by bright objects behind it.
    The clear acrylic produces a double image: a reflection from both the front surface and the rear surface. The clear acrylic could be replaced with a front-surface mirror so you can use a tenth the amount of LED current to get the same visual brightness, and remove the double image at the same time. (A mirror would also save the trouble of adding a black background)

        1. if you’re looking for efficiency there’s no point in doing all of that, simply put the led matrices vertically, maybe with a red pass filter. but this was specifically made to be like a HUD. for better viewing one could use thinner acrylic (maybe the diffuser behind laptop LCDs could do the trick) or a one way mirror, if I’m not mistaken (reflect the LEDs on the front, and whatever image comes through the back is visible)

          But it’s fine as it is! It works and it’s simple…

    1. Can you really do that? I can imagine how to make the numbers look shorter, even if I’m not sure of the final result (they should also look tilted away, since it uses the Pepper’s ghost principle) but not taller.

  2. It reminds me of the instrument display in a 2004-2009 Toyota Prius. The display is flat on the dash, in reverse, reflecting off a panel above it. There’s zero advantage at all VS having the VFD panel being directly viewed.

    I wonder if Toyota was planning on making it a HUD style then after it was too late to change the display around for direct viewing (parts already in production) they decided to de-HUD it and went with a hooded design with the angled reflector with black behind it?

    I thought it was a direct view VFD until I went to see about putting a piece of flat black cloth over the part of the dash that reflects a fuzzy green line onto the windshield at night. Turns out it’s direct shine from the display shooting just over the top of the ‘hood’ above the reflector.

  3. It’s like a 90’s kids project LOL. I love “The clock gets accurate time from an NTP time server over WiFi, thanks to the ESP32 microcontroller that runs the show” it shows todays weird developers mindset. How to make a simple thing really complex. That’s why Apple just do incremental as Garmin, Google and so one. Their developers doesn’t have any bit of useful creativity

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