long duration timer...some thoughts

Gang!

I'am tinkering with a project and need a timer that will run from say 10 minutes, output a pulse (either low to high or high to low) for say 1 minute and then reset and repeat the time process over and over and over.

timer counts 10 minutes, output goes high for one minute, counter resets and starts counting down another ten minutes.

the time need not be super accurate to the 9th degree, and in fact can wonder around a bit. Adjustable time would be nice with either a dip switch or small trimmer pot.

I have been kicking around a 555 running oscillator, a ripple counter and a one shot after that..

No microprocessors!!

So that's the project.. any ideas??

thanks.. mike

You might try a CD4060 14-stage ripple counter. It has a built-in oscillator. For a 10 minute delay at the 14th stage output, you would design the oscillator to run at about 27Hz.

Thanks carl...

but now I wonder... the output from the 4060 is going to be just a pulse, so I will need to lengthen it some what.. I need from 10 seconds to a minute,

how does one reset the 4060 after the 14th stage output?

the circuit will remain powered up at all times and unlike some of the long duration timers, there's no "START" or RESET button to press.

Like that pink bunny... it just needs to keep going and going and going.

mike

How about a 4060 followed by a 4017?

a 4017? Is that not a decade counter? How about a quick schematic? I even thought about just using a 555 for the short timer. Don't need real accurate timing.

https://www.electro-tech-online.com/threads/4060-oscillator-problem.18706/

should give you the idea.

The 4060 has two inverters that can make an oscillator, and with a 14 stage divide, the oscillator can be quite fast (about 250 Hz) and the output will be a square wave with a period of about 1 minute.

You never need to reset the 4060. It will just go back to zero itself.

You can use two resistors and a capacitor to add to the 4060 to make the oscillator. There are standard circuits for that.

You connect the clock input of the 4017 to the Q14 output of the 4060. Then the 4017 will count up in about 10 minutes, and go back to zero itself.

Any of the outputs of the 4017 will do what you want, i.e. go high for one minute once every 10 minutes. There is no need to reset anything, and you only need one basic oscillator that controls the speed of the whole lot.

The duty cycle will be fixed at exactly 10%. You don't have to adjust it. However, if you ever want a different duty cycle, you will need a different approach.

Thanks...

I got some 4060's on order from mouser and plan on doing some tinkering. Now that I don't have to reset the 4060 after it times out, makes things a bit easier.

Get a simple long duration timer circuit here:

**broken link removed**

Thanks,
Swagatam.

A 1µF capacitor is quite large at 230V AC, a small 1VA transformer will probably take up less space and be much safer too.

I'd recommend using a half wave rectifier and a TRIAC which uses much less current enabling a smaller 220nF capacitor to be used.

AC capacitors are quite smaller and permanent nowadays,I have used a capacitor which is not more than 2 by 2 cm. in size.

thanks,
swagatam.

Another long period 4060 timer with a monostable pulse output: **broken link removed**

Ken

The 0V connections to the ICs are missing on the schematic.

I think the ICs' ground pins are referenced on the -ve line along the bottom of the schematic.

Ken