Detecting AC power

[StealthRT]

Hey all, i am looking to do a little project and was needing some help with figuring how to go about it.

What i am looking to do is this:

I would like for my TV to come on automatically when the power goes out then comes back on. Normally, when the power goes out and you had the TV on, it would not come back on when the power comes back. I am thinking of setting up some TV "billboards" in a few retail places and i need a way to keep them on 24/7 without any need for users to interact with it (turning it back on if the power goes out, etc).

I am just looking for a simple schematic for an AVR-type (ATMEGA, Arduino) chip that i can hook up, detect the AC once it comes back on and send a signal to 2 wires to "click" the power button to turn the TV back on. (of course, only once would be needed after the power comes back).

Any help/ideas would be great!

David

 

[MikeMl]

I have used a small 5Vdc Wall-Wart as a "AC power is ON" detector. The transformer in the wall-wart takes care of the AC power isolation. It's output is a "logic level"; 5V when AC is on, 0V when AC is off. You could even power the "push-the-start-button" circuit from the wall-wart

 

[StealthRT]

Hey thanks for the reply there PMMikeMl. However, i'm looking for a solution that uses whats there on the TV (like the power cable for the TV). I really dont want to have something else have to be plugged in. But thanks for the suggestion

David

 

[mneary]

You would need to have access to the schematic. There is probably a standby supply inside the TV which you could use for your purpose.

When we know more about the standby supply (voltage, etc.) maybe we can make some suggestions. You also need a signal (logic level) that tells you that the TV is "on".

This may not need a micro. A simple 555 can 'push' the button when the AC mains comes on, and then be inhibited when the TV is operating.

My newest TV comes back on when the power returns, so you might be able to solve the problem by selecting the right TV. (I think it was a menu choice for my TV.)

 

[HarveyH42]

If you have frequent power outages, you might consider a small UPS (cheap these days). For $40 bucks, the TV stays on, plus you get some protection from surge and brownouts, which are a little rough on electronics.