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The inspiration or should I say frustration?

Whatever I do and publish through Clock-It, I get a regular supply of people contacting me to say how lovely my clocks are but they ever so slightly want something totally different. The conversation goes something like this:

  • Enquirer: “Hi I am looking for a design for a clock that is like yours but I have a great idea. I am sure it would be easy for you to do this for me.”
  • Me: “Well my clock doesn’t do that. If your idea is great, go away and do it.”
  • Enquirer: “I don’t have any programming skills or electronic skills and I want you to do it and it would be easy for you to do it for me for nothing.”
  • Me: “But I have enough ideas of my own I want to do.”
  • Enquirer: “Why won’t you help me?”
  • Me: “Because I have spent a lot of time in the past helping people who have usually run away without even a thank you once they got what they wanted. If it works out like this then you get what you are after, while all I have had is wasted time and money.”
  • Enquirer: “It will be really good and I will tell all my friends you did it for me.”
  • Me: “Sorry, no.”
  • Enquirer: “But I have this really really great idea for a case and all I need is the electronics to go in it.”
  • Me: “OK, so go and learn how to do it. Here are some very good websites.”
  • Enquirer: “But you could easily do this for me.”
  • Me: “OK, we will make two prototypes. I do the electronics, you do the cases and we keep one each. That way at least I end up with something too, if the idea goes no further.”
  • Enquirer: “I don’t want to do that, but I will pay you for it.”
  • Me: “That is not a service I offer and you couldn’t afford my time anyway. It will cost hundreds.”
  • Enquirer: “But the components cost pennies and you can get it made in China for almost nothing. Don’t be ridiculous, you are so rude you electronics people, I’ve met people like you before.”

In this particular case the person wanted the clock to do something VERY different and complicated, remote controlled and by the way, it had to be small, about 5cms or 2″ square.

The electronics

Later I thought about it and decided I could make a clock board small enough to fit 5cms while still being able to hand solder the LEDs. I laid out a PCB.

I emailed the PCB files to Seeedstudio and got ten boards back a week or so later.

All wired up and working. A red one and a blue one with 0805 sized LEDs

A case for the defence

Above: my first case idea imagined a little desk clock like this, so I did a visual of it in laser-cut acrylic and didn’t like it at all.

Above: my second design idea imagined the case above.

By this time I had the boards back, which were square. With hindsight they would be better as circular PCBs, but I was committed. The black shape in the middle is the power inlet, plugged in from the back. At the back a ring clips on with a friction fit to keep all the acrylic segments secured. It works well.

Below is the complete kit of laser-cut acrylic parts I ordered, again from Seeedstudio.

4 comments on “Charlieplexed miniball clock
  1. Sujith says:

    Hi,

    Nice dsign..
    which software you’re used to design the PCB and case?

    • clock-it says:

      I use Osmond PCB on the Apple Mac for PCB design and I use an old version of Freehand for vector artwork because it is so much better than Adobe Illustrator.

  2. Dave says:

    Great site. I found it while searching for charlieplexing 132 leds.

    My idea is to use a circle of 60 leds for the seconds. A concentric circle of another 60 leds for minutes and the third circle having 12 leds for the hours. I bet it’s been done before but I am just learning how to program PICs in Picbasic pro and it seemed like a fun learning experience.

    Congratulations on your clock designs.

    • clockit says:

      Because of the animation in my clock, the LEDs always appear to stream out of the minutes and disappear into the hours. So a second circle of 60 LEDs is not really necessary.

      Even in the simple mode, with two dots indicating the hour and a ring of 60 showing the minutes and seconds, it is very obvious which is the minutes and which is the seconds. It seems like overkill to have a separate ring for minutes and seconds. Not to mention a huge nightmare to design a PCB and solder on all the LEDs. The Charlieplexing won’t be an issue – I’ve done 144 LEDs without issue – it will be the PCB layout. I wish you luck with that.

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