I'm looking for a simple circuit that will give me a short "ding" when a light located well out of view is switched on.
Sitting at my computer I cannot see my driveway, which has a motion sensor 110vac light overlooking it. When someone approaches and rings the doorbell, it takes a minute to get to the door, and quite often they are gone.
So I would like to setup a small simple light sensor I can mount next to that light, wired to my desk, that would give a gentle "ding" when someone approaches, giving me ample time to get to the door.
I could plug it into a USB port, or charger or a cuppla AA batteries for power. Not 110vac powered.
Any ideas?

 

Light-dependent-resistor, 555 monostable, buzzer.

 

A circuit like this should work for you.
T1 is a phototransistor.
For your purpose you don't need the switch or the touchplate.

 

Any ideas?

You could put a note on your front door with your mobile number. Then you can just tell them to go away or that you'll be there in a minute.

 

Hi.

Any ideas?

How about this:

Wireless Doorbell

 

How about this:

Wireless Doorbell

He already has a doorbell.

 

You could put a note on your front door with your mobile number. Then you can just tell them to go away or that you'll be there in a minute.

Tried that. People don't read. And why make public my cell #?

 

He already has a doorbell.

Exactly!! I need to know someone is coming before they ring the doorbell.

 

Did you look at the circuit I referenced?

 

No, no, no! @nerdegutta , I thought of that as well.

You don't use it as a doorbell. You replace the pushbutton contacts with a photosensitive circuit. Then, when the light goes on?, it wirelessly activates the sound. In other words, hack a wireless doorbell for your purpose.

 

No, no, no! @nerdegutta , I thought of that as well.

You don't use it as a doorbell. You replace the pushbutton contacts with a photosensitive circuit. Then, when the light goes on?, it wirelessly activates the sound. In other words, hack a wireless doorbell for your purpose.

Of course you do! Silly me! Why buy a ready made products, when you can Rube Goldberg something you already have.

 

A circuit like this should work for you.
T1 is a phototransistor.
For your purpose you don't need the switch or the touchplate.

That looks interesting, but I have a few questions.
1-What changes to the circuit are needed to eliminate the switch and touchplate? Do I just simply delete them?
2-I just want a single "ding" not music. How do I get that?
3-Can the SCR be located remotely with just 2 wires? And how far?
4-How do I adjust the sensitivity of the photo-transistor? It needs to be insensitive to ambient light. The motion light is far brighter than ambient.
thanks

 

Of course you do! Silly me! Why buy a ready made products, when you can Rube Goldberg something you already have.

A bit more complex than I wanted! LOL And it didn't go "ding" at the end.

 

Oh... right, I forgot that part.

 

Wired or wireless? Wireless - an ebay wireless doorbell modified to transmit when a light sensor is tripped. downside - battery life.

Wired - 6.023 x 10^23 circuits to choose from. The good ones do not use a 555.

ak

 

Wired - 6.023 x 10^23 circuits to choose from. The good ones do not use a 555.
ak

So what would be a good one or 2 or 3 to choose from??