Here is a interesting project, for a electronic magazines.

In a Australian magazine "Silicon Chip" they had a project "PIR triggered mains switch" this is where if someone moves in front of a PIR device, the unit switch some main appliance on, for "set" time intervals from 7.5 Seconds, 15s, 30s, 1 minute, 2m, 4m, 8m, 32m, 64, 128m. and switches it off after that time

I see "Everyday Practical Electronics" magazine published the same project in their magazine the last month or so.

I changed the PIR for a infra red remote reviver and modified the circuit a little, so if I dont use the TV or DVD remote in the "set" time the TV switches off, Great for the bed room TV for when you fall asleep, you wake up with the TV not still going. I found a good time is 64 minutes, all you have to do is adjust the sound level or something else within the hour and the TV still stays on. And I love it sometimes I forget to use the remote in a given time and the TV just switches off (well their is nothing worth watching on TV anyway) sometimes I just leave the TV off and go and do something else, sometimes I am doing something else when TV automaticly goes off.

I have been meaning to add on a extra circuit to sound a buzzer (would have to be low volume not to wake you up) or light a LED just before the unit is about to switch the TV off, the "PIR triggered mains switch" unit also has a press switch where you can manually turn the appliance off but I was also thinking of adding a extra switch to manually turn the appliance (in this case the TV) on, this is when you are watching the TV and it suddenly goes off and you cant find the remote to turn the TV back on in a hurry.

I did send a email to the magazine telling them of my project, but never got a reply, and only used the ready available kit because I could not be bothered to build the project on Vero board and go and get the parts.

 

Pretty cool concept; you could use that for any appliance I guess. As for the T.V., most manufacturers have been including a sleep function in the TV setup menu for years.

 

I have seen the sleep function included in a TV, they seem to be not as good in my opinion, my TV does not have that feature. and at this time when the local Analog TV station switches off in a couple of years time I am not looking forward in rushing out to buy a digital TV, and might just flag the whole idea away in continue to buy DVD's of old TV program that were made prior to when pay TV along. For example most of Saturday on one station is all cooking programs, Guess what they have at night during most of the week? If you did not guess it, programs on fat people.

 

I see "Everyday Practical Electronics" magazine published the same project in their magazine (April 2011 PIR Triggered Mains Switch Switch almost any plug-in mains-powered device using a PIR in conjunction with this controller).

 

Please where can I get this magazin?

 

I have seen the sleep function included in a TV, they seem to be not as good in my opinion, my TV does not have that feature. and at this time when the local Analog TV station switches off in a couple of years time I am not looking forward in rushing out to buy a digital TV, and might just flag the whole idea away in continue to buy DVD's of old TV program that were made prior to when pay TV along. For example most of Saturday on one station is all cooking programs, Guess what they have at night during most of the week? If you did not guess it, programs on fat people.

Let's try to understand this. You plan to build a time-out system to shut down your old analog TV, but you think that the content of forthcoming digital services will be so poor that you may abandon watching off-air?

Why bother with the timer then, in a couple of years time you won't be watching it much anyway.

 

You should impliment a LED to flash 10 seconds before turn-off-time.

That way, if you haven't touched the remote because you are watching a movie, and the volume is fine, you will see the indicator letting you know the tv is about to shut off.

In a microcontroller, you could simply assign a variable

alert=Turn.Off.Time(in seconds) -(minus) 10seconds

When counter = alert raise a pin to high(5v) and have a blinking LED connected to that pin.

You can use a standard LED, but it would require more programming.

Then, when the remote is used, the timer resets, and the LED pin resets to LOW(0v)