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Physical talking clock — Parallax Forums

Physical talking clock

I'm looking for a suitable microcontroller for the below specs. Considering the propeller 1 or some arduino board (which i'll probably need someone to help make sense of). Any advice welcome!

The use case is for visually impaired - they'll press a button and it'll announce the time (in mandarin).
I'll be likely re-writing the audio file, as well as the programming, so no hard soldering of the sd card, or the use of ROM I presume. It doesn't need a UI or dashboard or any other alarm features.


  • speaker
  • sd card - for storing .wav files (audacity, 1 file and chop up for consistent volume)
  • sd card slot - solder on or buy a board with it.
  • buton
  • microcontroller to listen to button input
  • clock - [DS3231 RTC]
  • battery box
  • 3v battery


  • evanhevanh Posts: 15,338

    One nice thing with using the Propeller is it will be relatively easy to set it up to load next individual spoken word while the previous word is being output to the speaker. That way less time is required to piece it together. Or able to use higher quality samples in limited RAM.

  • Thanks @evanh . Can you elaborate how that works? I'm totally new to this actually so any help is welcome.

    And would you recommend the propeller 1 based on my requirements/specs?

  • evanhevanh Posts: 15,338
    edited 2024-04-07 09:37

    Hehe, always recommended. :)

    Basic idea is setup the speaker module (object) to run independently in its own core (cog). It simply waits for an audio buffer to be played filled and plays it, then waits for the next.

    The main object can handle the sequence of waiting for a button press, then loading the first word into a buffer signalling the audio player to start from that buffer. The main object then immediately moves on to loading the second word into a second buffer and signalling it is ready to play as well. It'll then have to wait for the first buffer to come free before loading the third word into that ... rinse and repeat until sentence is complete. Then go back to waiting for the button press.

    EDIT: Fixed the typo.

  • Hi,
    If the device shall run only from batteries, then I would recommend to have a very close look at power consumption. And if you want to use a module, then often its voltage regulator alone will draw too much current, so you have to switch off the entire module.
    For AA cells with 2500mAh and 1.5 years 2500/365/1.5/24=0.19mA.
    Using mains power supply with battery backup would open up much more possibilities.

  • If it were me I would lean towards a Phone app. Either something that already exists, or create my own. Even a Web based app that could run on a Phone or a PC.

  • iseriesiseries Posts: 1,472

    @"Beau Schwabe" , If the person is blind how is he going to see a button on a phone or even be able to call up the app to push the button.

    There are very few buttons on a phone and a lot of buttons on a PC.

    This project calls for the:

    Now how to replace the guts with a clock.


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