Close circuit timer with adjustable frequency

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Discussion Overview

The discussion revolves around the design and implementation of a timer circuit using a 555 timer, specifically for triggering a relay to close a circuit. Participants explore the requirements for adjustable timing between 0.3 seconds and 1 minute, with a preference for a visual indicator like an LED for calibration purposes. The context includes both theoretical and practical aspects of electronics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant expresses a lack of experience with electronics and seeks a solution for accurately controlling a timer circuit for a camera shutter.
  • Another participant suggests that the 555 timer is a suitable choice and provides links to application notes and kits, implying that the original poster may need to improve their understanding of electronics.
  • A different participant notes the importance of timing component tolerances in the 555 timer's performance and recommends using an oscilloscope for more accurate timing measurements instead of a stopwatch.
  • There is a suggestion to explore simple electronics kits as an alternative for those who may not be ready to design their own timer circuit, emphasizing the educational value of assembling such kits.

Areas of Agreement / Disagreement

Participants generally agree on the utility of the 555 timer for the intended application, but there is no consensus on the best approach for someone with limited electronics experience. Multiple suggestions and resources are provided, indicating a range of perspectives on how to proceed.

Contextual Notes

Some limitations include the original poster's self-identified lack of ability in electronics, which may affect their understanding of the proposed solutions. Additionally, the effectiveness of the 555 timer is noted to depend on the quality of the timing components used.

Who May Find This Useful

This discussion may be useful for individuals interested in basic electronics, particularly those looking to implement timing circuits or seeking guidance on using 555 timers in practical applications.

jon_k
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I've been looking at 555 timers and other stuff but don't have the ability to control this stuff.

I want to trigger a circuit close with a relay, with accurate adjustments to a dial.

I want to be able to accurately control the trigger of the timer between 0.3 seconds to 1 minute.

So something with an LED would be nice, so I wouldn't have to use a stopwatch to check the calibration prior to deployment.

(This is for remotely triggering a camera shutter based on time passed.)
 
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The 555 is the old standby that you want. If you truly "don't have the ability to control this stuff" -- I presume you know nothing about electronics -- then you may not be able to continue with your project. But I would guess that you can make some more headway...

I googled "555 timer application notes" and came up with:
http://www.doctronics.co.uk/pdf_files/555an.pdf
that has a bunch of information about how to use it buried in the technical noise.

You might also find a kit that does what you want, like this one:
http://www.goldmine-elec-products.com/prodinfo.asp?number=C6479

good luck
 
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Using a stop watch probably isn't too accurate. Watching the pulses on an oscilloscope would give you better much results. Also the 555 is very dependent on the timing components i.e. the tolerances of the resistors and capacitors used to set the time.

That being said, I've used them in many applications and the best way, IMO, to learn it is to play with the application notes in the chips data sheet. "www.cs.put.poznan.pl/wswitala/download/pdf/LM555.pdf"[/URL]

BTW the LM556 is a dual timer (two 555s in one chip)
 
Last edited by a moderator:
jon_k said:
I've been looking at 555 timers and other stuff but don't have the ability to control this stuff.

I want to trigger a circuit close with a relay, with accurate adjustments to a dial.

I want to be able to accurately control the trigger of the timer between 0.3 seconds to 1 minute.

So something with an LED would be nice, so I wouldn't have to use a stopwatch to check the calibration prior to deployment.

(This is for remotely triggering a camera shutter based on time passed.)

Welcome to the PF.

Another approach would be to see what kind of simple electronics kits are available for timers. I googled electronic kit timer, and got lots of good hits. At least this way you wouldn't have to be able to figure out how to design the timer circuit if you weren't ready for that yet, but you would still be able to see how the circuit was designed (most kits come with an explanation of how the circuit works), and you would be able to put the kit together yourself, to get some experience with simple assembly and soldering.

http://www.google.com/search?source...z=1T4GGLL_enUS301US302&q=electronic+kit+timer

.
 

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