A Talking Clock For The 21st Century

The Talking Clock service is disappearing, and it’s quite possible that few of you will be aware of its passing. One of the staples of twentieth-century technology, the Talking Clock service was the only universally consumer-available source of accurate time information away from hourly radio time signals in the days before cheap radio-controlled clocks, or GPS. You’d dial (on a real dial, naturally!) a telephone number, to be greeted with a recorded voice telling you what the time would be at the following beep. Clocks were set, phone companies made a packet, and everybody was happy with their high-tech audio horology.

[Nick Sayer] used the USNO Master Clock telephone feed to see in the New Year, but had to make do with a voice from another time zone. It seems that there are no services remaining that provide one in Pacific time. His solution to the problem for a future year? Make his own Talking Clock, one that derives its time reference from GPS.

At its heart is a SkyTraq Venus838LPx miniature GPS module coupled to an ATMega32E5 microcontroller. The speech comes in the form of pre-recorded samples stored on an SD card. There is a small on-board amplifier to drive a single speaker. For extreme authenticity perhaps it could be attached to a GSM mobile phone module to provide a dial-up service, but he’s got everything he needs for a New Years Eve.

Want to hear what that that bit of nostalgia sounded like? Check out the quick clip below. As for modern replacements, we’ve had at least one talking clock here in the past, but not one using GPS.

GPS satellite image: NASA [Public domain].

24 thoughts on “A Talking Clock For The 21st Century

  1. “The Talking Clock service is disappearing, and it’s quite possible that few of you will be aware of its passing. ”

    I’m sure some here remember the passing of the telegraph. :-D

  2. I wonder if services like this had some special arrangement in the telephone office so that multiple calls could be connected to a single line. Otherwise it seems that all lines would get full at e.g. new years.

    1. Traditionally, they were a built-in service provided by the phone company. An entire prefix would just be shunted to a single audio circuit. I grew up in Southern California, and for us 853-xxxx was it. In Northern CA, it was 767, which people often remembered simply as POP-CORN.

      Originally those numbers were created to take the load off of operators who spent an inordinate amount of time answering calls merely asking for the time.

      They fell out of favor with the increasing availability of clocks on connected devices whose time was always accurate. Nowadays, of course, nearly every Internet connected thing intended for human use has a clock set and disciplined by NTP, and nearly everyone in the developed world has one of those at hand continuously.

  3. I know our public radio station had the line, I was shown this in a private tour and have heard it over the air. Purdue-engineering. That sharp hard pronunciation (Navy) that gets through, where wimpy kindergarten teacher talking (WBAA) don’t.

    1. In the US, at least on a national level, there’s always the USNO’s service. You can also call a phone number and listen to WWV and WWVH.

      The irony there is that the USNO is, in fact, the US’s representative in the global horological Jedi Council that establishes TAI/UTC, and as such, for civilian purposes, represents THE source of exact time, but turning it into audio, then transmitting it over our modern digital telephone network tosses the majority of the accuracy right out the window.

      1. In fact, I just tried that experiment. At my disposal, I have Verizon wireless and Comcast. Comcast was easily more than 250 ms of latency and Verizon much worse (to be fair, I have a Verizon femtocell running here in the house, which undoubtedly makes it worse). The talking clock makes it fairly easy to measure by ear as opposed to trying to mix measurements by eye and ear.

  4. This is one of the things that really puzzle me. I get that old and unused services get disbanded if they block resources (frequencies come to mind). But the Talking Clock? I mean, how incredibly huge can the upkeep on this service possibly be, especially since nowadays phone lines are all digital and virtual anyway, and such a simple voice service could be run on the infrastructural equivalent of a toaster oven.

    1. it might just be case of old equipment failure, and not seeing a need for replacement. With newer, possibly better, possibly more accurate ways of doing the same, then why?

      and this is from a 51 year old fart….

  5. Interesting note: GPS chips tend to have processing resources to spare, and the SkyTraq chips in particular have released an Arduino-compatible board and environment that lets you easily run your own code alongside the GPS code.


    So if anyone’s looking to replicate this project or similar, you could probably do it all in a single chip. :)

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