Varying another resistor sets the output pulse width.

Where would that be with the CD4060 circuit?

Someplace I haven't seen posted before.

On the oscillator, unfortunately it would adjust the timing of everything.

Nope.

ak

 

It’s early in the morning. I get U and I confused a lot, not to be confused with getting you and I confused.

The word for those types of things is the malapropism.

Malapropism - Wikipedia

 

Aren't there a ton of watchdog chips out there from the 80's-90's?

ak

 

Here is a concept schematic for what basically is a watchdog timer.

Note: This is a 1:60 scale model. See #27.

ak

 

I am a believer in running the oscillator fast and using a counter.
Here is two different 6 pin ICs that do timing form very 500uS to hours.
In this example the first time could be set to 2hr while the last one set to 1 second.
Internally there is a divide by 1 to 2 million counter.

 

A.K Called it right in post #16!! A CD 4060 with an oscillator of one pulse every few seconds, so that some higher counter output would go high every 180 minutes. That is well within the reasonable components size realm, and a reasonable counter rate. and then the device that was reset can reset the counter.

 

Updated schematic with corrected component values.

ak

 

The word for those types of things is the malapropism.

Malapropism - Wikipedia

Actually, I think it is called “fat thumb.”

 

Here's my version, if anyone is still interested. Yes, it takes 4 chips, but it is accurate!



Looking at my previous circuit, which I couldn't access whilst drawing up this one, I appear to have gotten the two Xtal load capacitors swapped. Ooops. It's preferable being a trimmer anyway!