Hi, I'm making a dummy led camera with the goal of it (the led) lasting three+ months (the more the better obviously) and was wondering if anyone could help me with these questions?
What led, resistor, and battery should I use?
And, any rough ideas how long the led would stay lit on a 12v led with a built in resistor and a 4 amp sealed lead acid battery?
Buy a blinking LED. One of my sons toys came with a little blinking red LED powered by a couple AA batteries. It wasn't very bright at the end but it was still blinking 6 months later, should last an incredible amount of time powerd from a couple of C or D cell alkalines.
I have a thing I saved out of the trash a long time ago. Its basically 5 white LEDs that blink maybe once a second. It was used in a sign that hung from the ceiling in a retail store. It used 4 D cells. It blinked for atleast a month 24/7 before it got tossed due to new seasonal signage. It was still blinking a long time after I saved it. If you use a single red blinking LED, 2 D cells could last you a long time. 3 months easy.
yeah, a security camera would normally have a red, diffused indicator type LED, no real need for a bright one. This seems to be a perfect application for a LED with a built in flasher. Then the OP also doesn't have to fit any circuitry into his camera.
I'd opt for the ready made flashing LED as suggested. When you start connecting superbright or multiple leds to a security camera, it can suggest then, that it's a dummy camera. Real CCD cameras use small leds to indicate operation... not to attract attention.
The blinking led's I've gotten are not 50% duty cycle, it's at least 25% or less, the extra costs of the components and the time to assemble the board is a waste of time for someone that just wants a simple led blinked. And considering that 2 D cells will already last a year or more in said device a little extra efficiency is not a problem. What might be a problem is this being a fake security device, which may be outside or in a real environement where somethign could go wrong with one of the components on the board. blinking LED's are fully encapsulated.