Hi

I have be playing around with 555 timers and I have on order cd4060. I am trying to make a timer that goes for one second a logic high or low ( selectable with switch) every 15 mins. I notice that 555 is not good for long time cycles. So I think a cd4060 would be better for this.

Sorry I don't want to mess around with MC, PIC, etc I don't want to learn programming.

Thanks

 

Hi tim,
Welcome to AAC.
What timing accuracy are you requiring?
E

 

Well, it don't have to be real accurate. If I recall, if I need more accurate, I could add a crystal to the 4060. What is the accuracy of the 4060 without crystal? plus or minus 30 seconds?

 

Hi,
The accuracy is not dependent upon the 4060, but the driving oscillator.
E

 

Hi

I have be playing around with 555 timers and I have on order cd4060. I am trying to make a timer that goes for one second a logic high or low ( selectable with switch) every 15 mins. I notice that 555 is not good for long time cycles. So I think a cd4060 would be better for this.

Sorry I don't want to mess around with MC, PIC, etc I don't want to learn programming.

Thanks

What happens if you are unable to meet your objective with the chosen parts? I guess you'll be SOL.

 

you mean with the RC components that are being used? plus or minus 30 second is that possible?

 

What happens if you are unable to meet your objective with the chosen parts? I guess you'll be SOL.

lol well that could be, then I will have to try to figure something else out

 

Hi,
An any error in the basic oscillator frequency will be cumulative over time, either increasing or decreasing the timed periods.
E
How long will the project be running?

 

Hi,
An any error in the basic oscillator frequency will be cumulative over time, either increasing or decreasing the timed periods.
E
How long will the project be running?

Ya, I figure that would be the case. i will have to build it and check it and go from there

 

Ohh sorry didn't see your other message, it would be running 24/7

 

it would be running 24/7

hi tim,
Over what time period.?
E

 

cd4060 is not just counter - it also has an oscillator. so using crystal would make it much more stable. all you need to do is decode state that you want to reset it. and using XOR gate would allow for easy selection if the output is mark or space

 

hi tim,
Over what time period.?
E

it would be on 24/7 meaning every 15 mins it would go high or low throughout the 24 hours

 

cd4060 is not just counter - it also has an oscillator. so using crystal would make it much more stable. all you need to do is decode state that you want to reset it. and using XOR gate would allow for easy selection if the output is mark or space

yes I think I would try without a crystal to see how it works, if need I could add a crystal later

 

hi,
For how many days, weeks or months, will it run uncorrected?
E

 

if you want oscillator that gives pulse every 15min, then period is 15min. the CD4060 is a 14-stage ripple counter and lowest crystal frequency is 32k. so output of CD4060 would be about 1Hz. to turn that into 15min interval you need another counter to further divide by 900 (15min*60sec = 900 seconds). this would then reset both ICs. the reset pulse can be used to trigger a monostable for 1sec output.

 

hi,
For how many days, weeks or months, will it run uncorrected?
E

this would be on 24/7 / 365 days or in till the world end

 

HI,
OK, then you need a quality crystal, a 555 will not be suitable
E

 

lowest crystal frequency is 32k. so output of CD4060 would be about 1Hz

Actually 2Hz.

 

if you want oscillator that gives pulse every 15min, then period is 15min. the CD4060 is a 14-stage ripple counter and lowest crystal frequency is 32k. so output of CD4060 would be about 1Hz. to turn that into 15min interval you need another counter to further divide by 900 (15min*60sec = 900 seconds). this would then reset both ICs. the reset pulse can be used to trigger a monostable for 1sec output.

thats ok, so two 4060? you're referring to the built-in oscillator 32k or external crytsal?