Thank you all--Parts will be arriving soon and it should be fun to see what happens. Will let you know.You could use triggers and tact them at 1 sec or 1 min to get a digital clock?
For your needs, you should find a CMOS 555 just fine. The very first paid design I did (while an undergrad and before I knew about digital logic, let alone microcontrollers) was a 15 minute "hospitality timer" for the Taco Bell I worked at. It was used to let the staff know that it was time to go out and check the seating area and clean it up if necessary, since when we were busy it was the first thing to start getting neglected. It worked great, even though the RC sizes were significantly different than what the book would say because of the capacitor leakage current -- in fact that's how I really learned about capacitor leakage as a real design factor.Yes, the reed switch can be mounted at a distance from the jamb. However since it is a boat and a door left open will bang back and forth when it rolls, all doors and drawers tend to be firmly shut, so not worried about that, but maybe a good idea in any case. Voltage is 12vdc although can run up to 14 when engine is running and current draw is < .25 amps.
I have no claim on a 555 and if a CD4060 would work better that that is fine too. I notice that there is no pot, so figure that you have calculated the values for ≈ 5 mins. Anywhere from 4 to 6 is fine.
I'm assuming from the diagram that the output here controls the ground on the timed output/lights, and the left connection tab that runs to TR on the 555 remains open.
Where do you find these jobs? I don't believe that by asking randomly 100 shops I would get even 1 offer? How does this work even?For your needs, you should find a CMOS 555 just fine. The very first paid design I did (while an undergrad and before I knew about digital logic, let alone microcontrollers) was a 15 minute "hospitality timer" for the Taco Bell I worked at. It was used to let the staff know that it was time to go out and check the seating area and clean it up if necessary, since when we were busy it was the first thing to start getting neglected. It worked great, even though the RC sizes were significantly different than what the book would say because of the capacitor leakage current -- in fact that's how I really learned about capacitor leakage as a real design factor.
The key to this one was the phrase, "at the Taco Bell I worked at." So the answer of how I found the job was I applied for it. I was working as a co-op student at the National Institute of Standards and Technology (NIST) at the time (though it was still called the National Bureau of Standards back then) and the pay sucked. So I also worked part time at Taco Bell. My manager knew this and knew that I was learning about electronics, so he approached me with an idea for this hospitality timer and asked if I was interested in building one. I think he had the notion of trying to sell the corporation on it and getting a bonus if it was adopted. I got paid $50 for doing it, plus the cost of the parts.Where do you find these jobs? I don't believe that by asking randomly 100 shops I would get even 1 offer? How does this work even?