Electrical Engineers?

[somebodyelse Senior Member Find all posts View Profile Close somebodyelse]

Probably don't need to be an engineer, but okay... here's a question...

I'm thinking about making a timer circuit with a 555 IC The idea is to use a potentiometer or a resister enough to make it stay on for 10 minutes...

The problem with this circuit is that it need power. I want this circuit to only use battery power when it is operational.

Here's my idea. I have an Output for 12 volts that's temporary. It comes on only when certain conditions are met. thing is, I want this circuit to trigger this timer circuit so whenever the power arrives to the circuit it stays on for 10 minutes then automatically shuts off.

Now I was thinking of ways to shut the circuit off from battery power once the timer is up. without complicating the whole system (relays and such) but I can't figure it out.

using this basic circuit though, I'm sure that the timing function will die if power is removed prematurely

Adjustable 1-10 Minute Timer Project

How can you effectively turn on the power supply and start the timing process with a 12 volt momentary switch and have the circuit automatically shut out from the power (which is a battery) when the circuit is not in use?

[somebodyelse Senior Member Find all posts View Profile Close somebodyelse]

Nevermind... I figure if I just remove the "red" LED from that circuit it'll break the circuit but I'd have to then make sure everything else operates as planned... Gotta do that math... UGH!

[DemOne Banned Find all posts View Profile Close DemOne]

Been up for too long so I might be getting confused on what you're asking for, but you could use a small relay switch connected to the power for the red LED (or in place of the LED, since you wouldn't really have a need for it, right?), and once that's activated, it creates an open in the power circuit.
Red LED off = relay closed, power on to run circuit.
Red LED on = relay open, no power to circuit.

[somebodyelse Senior Member Find all posts View Profile Close somebodyelse]

meh... even more impressive... this has already been done before... in a prepackaged box for me... sweet. That's a really good idea... however, it'll still draw current... :-/

[DemOne Banned Find all posts View Profile Close DemOne]

Well, I have an idea that involves resistors, a pressure switch, a small motor, and a stick, if that would work...lol

[DemOne Banned Find all posts View Profile Close DemOne]

Well, I have an idea that involves resistors, a pressure switch, a small motor, and a stick, if that would work...lol

[Ravenously Senior Member Find all posts View Profile Close Ravenously]

You could use a scr transistor, or just a relay switch Alan Bradley makes several. Or you could do the entire thing with a PLC.

[not2big Senior Super ModeratorPEGym Hero Find all posts View Profile Close not2big]

Electrical Engineer joke:
An Indian reservation raised money and sent its brightest student to college. Upon graduating with a degree in electrical engineering he returned to be honored at a special dinner hosted by the reservation. After thanking all the members of the tribe for their support and monetary contributions, he inquired if he could repay them in any way. One of the female leaders advised that the path to the outhouse was dark and difficult to navigate at night and inquired if he would mind installing electrical lights to make the trip to the outhouse at night easier to travel. Once he had satisfactorally completed the job, he became known from that day forward as the first Indian to wire a head for a reservation.

I know, a bit old and lame. However, how often do you get to tell an electrical engineering joke?

[jb357 Senior Member Find all posts View Profile Close jb357]

Actually if the Indian was an electrical engineer he would of drawn the schematics for someone else to "wire a head"

[not2big Senior Super ModeratorPEGym Hero Find all posts View Profile Close not2big]

Actually if the Indian was an electrical engineer he would of drawn the schematics for someone else to "wire a head"

Picky, picky, picky.