Here's the situation - my dumbass son keeps forgetting to close the fridge door leaving it open for many hours at a time. I want to make sure he never forgets to close it by creating a circuit that will activate some sort of annoying siren warble and if left open for too long.
The question is.....
What component would everyone recommend I use to produce that sound? It has to be obnoxious, but obviously not loud enough to wake the entire house every time. Just an annoying sound that'll make him cringe lol. I'd rather not use an LED as it's a tad boring.
disclaimer: The intent is not to create some sort of cruel punishment, but more of a practical joke between us, give his budding interest in circuitry (we're both hobbyists).
Ahh yes, left open fridge door syndrome... Sounds like an interesting project and way to remind him not to spoil all the food.
There are a zillion buzzers, beepers & sirens with a huge variety of frequencies, volumes and patterns. Just depends on how annoying you want it to be. Given the amazing teenage tolerance for annoying sounds (that they normally call music), I can see this noise being left on for a very long time unless it gets YOU out of bed.
My first thought would be to actually use a small digital voice recorder pcb, i beleve they still sell them at RadioShack for $15 or so. The fridge could actually verbally remind him to close the door If you felt very adventurous you could wire the speaker remotely into his bedroom ceiling or a vent so he couldn't escape the reminder. Or if you put a Z10 remote light bulb fixture in his room, his lights could flash until he closed the fridge
Ok... i'm getting a little carried away... but hopefully this gives you a few ideas. Have fun! And good luck!
You could use a 555 timer to create an oscilator at a certain frequency and then put an output stage to a buzzer or speaker. You could set it up to be adjustable for volume and frequency as well. I'm sure you have something in mind, but you could use a 555 timer to set the "fridge open" time delay as well to enable or disable the buzzer.
My mom had a light sensitive, open loop gain, AB circuit. Her eyes saw that door open and the light on, she went balistic and went into Ass Beating mode. There was no discussion or warning......it just came out of left field.
Only activated once and it worked like a charm.....to this day, when I get cream for my coffee, I can't help but shut the door and I'm 50+.
That circuit you just described - It lit up a light in another room or how did she find out in the nick of time? Just curious...sounds funny.
Mallory makes several lines of buzzers and sirens. Sonalert is one of their trademarks. They range from less than 1$ such as the PB-1224PE-05Q to around $10 for the PS-522Q.
I had one idea that uses a timing circuit and one of those electric shock collars for pets, but I think it verges on child abuse. How about just attach a long spring inside the refrigerator to the door, so it self closes?