Building a Countdown Timer with a 555

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Discussion Overview

The discussion revolves around building a countdown timer using a 555 timer IC, with aspirations for accuracy and a range from 5 seconds to 36 hours. Participants explore the feasibility of integrating a 7-segment LED display and consider alternatives like using a crystal oscillator and microcontroller for improved accuracy.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant proposes using a 555 timer for a countdown timer but expresses uncertainty about its ability to accurately count down to the minute without a crystal oscillator.
  • Another participant suggests that a 4060 chip combined with a watch crystal would provide better accuracy, potentially to a fraction of a second.
  • A participant inquires about sourcing parts and expresses confusion regarding the specifications of various ICs, seeking guidance on what to look for when purchasing components for their project.
  • One participant provides a specific part number (DC4060) and mentions that it is part of the CMOS range, along with links to resources for finding these components in Britain.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best approach for building the timer, with differing opinions on the use of the 555 timer versus the 4060 chip. The discussion remains unresolved regarding the optimal components and methods for achieving the desired accuracy.

Contextual Notes

Participants express uncertainty about the specifications of ICs and the implications of using different components, indicating a need for clarity on how these factors affect the timer's performance.

Who May Find This Useful

Individuals interested in electronics, particularly those looking to build timers or similar devices, may find this discussion relevant.

tenacity2986
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Im trying to do just that, that is build a timer that countsdown accurately to the minute. Ideally this device should have a range of about 5 second countdowns to 36 hour countdown. I'd like to add a 7-segment LED display wired to count as well but I am not sure I think i can do that with a 555 without a crystal oscillator. What I am thinking might work is using a crystal oscillator in tandem with a microcontroller that will know the number of clockcycles a second are before decrementing the value on the LED display where at T=0, it should send a high voltage pulse to the output terminals, preferably high enough power such that it can accommodate turning a small dc motor on. Thanks for your help and valuable insight.
 
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Much better to use a 4060 chip and a watch crystal. Accurate to a fraction of a second without any adjustment.
 
Thanks for the honest feedback, however where can I find these types of parts? I've found so many different brands of ICs with so many specs most of which mean absolutely nothing as of now to me... What should i be looking for when purchasing a viable IC for my application?
 

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