Author Topic: Is possible to make a clock from a 555 timer?  (Read 2937 times)

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Offline LinkZ

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Is possible to make a clock from a 555 timer?
« on: May 19, 2015, 07:16:14 pm »
I've found this site (http://www.engineersgarage.com/contribution/digital-clock-without-microcontroller) which claims that is possible to make a led clock from a 555 timer and few other parts.
here is the schematics:

url immagine
Can this circuit work?
If yes, in the description it says that few basic and/or gates are required. Which should I use?
 

Offline Zero999

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Re: Is possible to make a clock from a 555 timer?
« Reply #1 on: May 19, 2015, 07:21:08 pm »
Not really. A clock made with an RC oscillator won't keep time and will drift all over the place.

Use a 32768Hz crystal and a divide by 15 counter to get a 1 Hz time base.
 

Offline German_EE

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Re: Is possible to make a clock from a 555 timer?
« Reply #2 on: May 19, 2015, 07:24:34 pm »
The 555 just supplies one pulse a minute to drive the first counter. All of the chip information is there apart from the AND and the OR gates, so have a quick look in a 74HC series catalog and see if you can find them

ANd yes, this will drift like crazy.
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Offline smjcuk

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Re: Is possible to make a clock from a 555 timer?
« Reply #3 on: May 19, 2015, 07:30:37 pm »
Built something similar to that in 1991. No idea what happened to it to be honest. Probably nicked the bits for something else.
 

Online Simon

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Re: Is possible to make a clock from a 555 timer?
« Reply #4 on: May 19, 2015, 07:41:40 pm »
Ypou can make a closk oscillator with unbuffered cmos gates and a 32.768 KHz crystal, I did this for a friend to make a 30 second ticker but used a microcontroller and fed the 32.768KHz in as an interrupt to keep time
https://www.simonselectronics.co.uk/shop
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