A Tiny Clock with a Retro Display

After having ported Contiki to his TI Launchpad platform, [Marcus] was eager to do something with it. He therefore built a simple clock with a vintage HPDL-1414 “smart four-character 16-segment alphanumeric display” and a msp430g2553.

The result that you can see above is powered over USB, includes a 3.3V LDO linear voltage regulator as well as a button, a LED, a crystal, and several passive components. Fortunately enough, the 5V-powered HPDL-1414 display accepts 3.3V logic at its inputs, avoiding the need for level translators.

The clock program is running on the ported Contiki 2.6 that you can find on his Github repository. [Marcus] is considering using a vibration motor to buzz every 20 minutes during work hours as a reminder for the 20-20-20 rule to battle eye fatigue: every 20 minutes, look at something 20 feet away for 20 seconds. A video of the system in action is embedded after the break.

18 thoughts on “A Tiny Clock with a Retro Display

  1. anyone know where one could pick up one of those HPDL-1414’s, or one of its successors?

    It looks great and I’d love to use it in a watch or something.

    1. Not suitable for a watch unless you’re made of batteries, or don’t mind charging it up every 30 minutes. (at least the displays *I* have, they may have some low current versions)

      1. The datasheet for the Siemens kind states 50mA @ 5V, +25degC and four chars on. 1mA if no char on. Not really material for an untethered watch, no. But, perhaps with some LiPo or sth, and recharging every now and then.. Don’t know. Running it at 3V works too, with dimmer characters and likely saves some power, but still…

      2. They used to have a button for displays on wristwatches to save the batteries:

        Check 5m28s in case the offset is omitted.

      3. I think those 14 (?) segments display would look cool for Mooltipass.

        I have a dozen of vintage plain 7 segments multiplexed display *without*
        any driver/decoders (that consumes extra current). Every uA counts in a
        watch.

        You just need to drive out one digit and its corresponding column inside
        a timer interrupt. It’s “10 lines” worth of code plus a character ROM.

  2. I have a bunch of those displays, the 1616 version too (or 1416?)
    The biggest problem is they’re current hogs. Some of the earlier displays, HP dot displays, were HUGE hogs. You had to build heat sinking into the PCB to keep them from melting….. Look great though…. Serial in, Serial Out… nice, but HUGE current hogs.

  3. Good job!
    I thought that there will be battery solution also. Now it seems that the best solution is to power the display only when needed (as in Nixie watch), ’cause otherwise it would drain battery quite fast. Not as fast as 4N51 or 4N54 displays though (and these look awesome too).

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