IEE clock

The IEE clock looks somewhat un remarkable at first glance. Upon closer inspection though, you’ll find out that there are 12 light bulbs crammed in there for each digit. The bulbs sit behind a curved lens with the numerals on it. When the appropriate one is lit, it projects the number on the front of the clock. While it isn’t new, it is certainly new to us. It is also interesting that you set the time by rotating the little dial on the top right. While it may be easier to set the time that way, it seems that it would be prone to getting nudged on accident.

[via the Hackaday Flickr pool]

21 thoughts on “IEE clock

  1. @anon
    i think he meant that the mtbf of the clock would go way down, as in how long would it run before one of the light bulbs would need replacing

  2. @anon

    “i think he meant that the mtbf of the clock would go way down, as in how long would it run before one of the light bulbs would need replacing”

    No, we would expect the clock to be 100% operational for at least the MTBF of the worst lamp. Since lamp failures are statistically independent events, more lamps don’t mean the MTBF gets lower.

  3. The time you’d expect before having to change a bulb is 1-(1-X)^n where X is the chance of bulb failure, and n is the number of bulbs.

    Since 0 ≤ X ≤ 1, 1 ≥ 1-X ≥ 0, (1-X)^(a+1) ≤ (1-X)^a, 1-(1-X)^(a+1) ≥ 1-(1-X)^a

    So this increase as n does (if X isn’t 1 or 0).
    But I think MTBF which is ‘Mean Time Before Failure’ *is* X, and is a value independent of bulb quantity, but more dependent on bulb *quality*. It could be mistaken as meaning ‘Minutes Till Bulb Failure’ though, but that isn’t a ‘thing’.

  4. this would have been epic win if it was posted ON 4/20 as well
    [S]btw, why the bulbs as opposed to somthing the clock making industry discovered 30 years ago, LEDS[/S]
    just clicked the article i want 1!!!
    btw, in purposes like this im guessing the bulbs arnt being driven at full power so they will have ALOT better mtbf than you might expect

  5. He claims to have found the things at a flea market for $10. I don’t believe him; he bought them on eBay.

  6. make tv show lost clock ???

    that sound is from supermarket check out counter!!!

    good luck email me when you do….

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