Help me solve this design problem PLEEEZ

A *small* battery holding the last timer state in a UC should work. Ok, if they tripped the thing out and left for the day they'll have to wait tomorrow. In any case, I agree with others. If it's a temperature problem, measure the temperature. ...and build in any alarms and margin to make sure noone gets killed! I'm glad it's *your* problem. ;-)

LOL.

underpinned by clearly successful problem solving methodologies.

There are lots of books about the relevant theories. There are far fewer books covering the practical aspects that are required to turn theory into practice. Even worse, there are few (if any) books (or papers) talking about things that didnt work, and why. This is the sort of knowledge that dies and gets re-discovered the hard way.

Cheers Terry

a 1mm air-gap in series with one of the leads works nicely.

Cheers Terry

"funster" schreef in bericht news: snipped-for-privacy@g14g2000cwa.googlegroups.com...

That's understandable. Using a micro there are other ways to achieve the same. Modern micros have a sleep mode in which they use hardly energy but keep all of their contents alive. A small battery can power such a thing in this mode for over a year. Of course you have the same problem when they can disconnect the battery but you can build in a five minutes delay for the first time the micro is started. Again, some work has to be done and again they may find a way to circumvent it. But what is the deal? After all it is only a warning device. It can be ignored, they can cut some wire, muffle the audible alarm using chewing gum and so on. If you can't trust the people working with the equipment, you have a real big problem but not a technical one. You may install a device that gathers data about the use of the equipment you want to protect and send that data to some computer to make reports of it. So you come near the $30.000 solution you did't like.

petrus bitbyter

He was paranoid about his designs. He wouldn't even let his girlfriend see his chip layouts.

John