Automatic countdown reset timer?

seems kind of vague, what's the meaning of "reset" and "trigger"

what sort of precision and approximate magnitude for the timer.

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Sounds like you already have a pretty good idea of what you are doing or want to do.

A single 555 monostable triggered by an inexpensive off-the-shelf motion detector with an external reset.

But you are probably leaving something out - like what precision do you want, and does time need to be adjusted with some degree of accuracy and will it change often, how user-friendly, etc..

5 minute time accuracy is fine.

You walk into a room, the motion detector sees you and it sends a signal to the timer/controller which activates a 5 Amp 110 Vac circuit for let's say 45 minutes..

If you walk around the room and the sensor sees you again within the

45 minutes; nothing happens.

Only after the timer counts down will that room sensor reset the timer..

However, If you, or another person goes into another room and its sensor detects movement withing the 45 minute countdown, the timer/ controller resets to 45 minutes.

Is this clear?

Perhaps I made it too complicated.

All sensor signals will set the timer to 45 minutes.

IOW After the last sensor detects motion and signals the timer, it will count down 45 minutes.

That would make it much simpler.

So, any sensed activity first resets the counter to 0, then starts it. When the counter starts, a 5 amp 110 VAC circuit is completed. The counter runs for 45 minutes. If and when 45 minutes is reached on the counter, the

5 amp 110 VAC circuit is opened. You've just described a motion sensor switch with a delayed off. They are commercially available.

Here's a link to one:

There are many other manufacturers that make motion sensing, delayed off switches that are used to turn the lights on in a room when there is activity, then turn them off x amount of time after the activity stops. Google to check out what's available.

Ed

n

Thanks Ed,

Good find.

A few questions:

Can all sensors control the same 110 VAC device?

The motion detectors are AAA powered do you know of any hard wired devices?

(I can't imagine them hooked to Wally-Mart chargers)

Thanks again.

Yes. But there is a limited range of 20' according to the info at the url cited above.

Yes, there are hard wired motion sensor switches. I've walked into rooms where the lights turn on upon entry - a bit startling the first time that happened - and turn off some time after I've left. Google to find the specs - I don't know what's available in terms of delay off times, area coverage, etc.

Ed

son

e g t

The auto room light is fine for that room.

The ghoal to is to have all the detectors in all the rooms control a single appliance elsewhere in the house.

I believe that the X10 system with an appliance receiver will do the job.

Many thanks