flashing led in car
Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=100110
Printed Date: June 02, 2024 at 12:53 PM
Topic: flashing led in car
Posted By: rwdbmwm3
Subject: flashing led in car
Date Posted: December 16, 2007 at 8:45 PM
I was just wondering what the best way to do this would be
(like the flashing LED's with cars that have alarms)
there is a circuit you can make with a 555 timer and 1.5V battery...how long would the battery last on this sort of circuit?
and there is also something you can buy from store... an led that runs off of your 12V car battery or something like that?
im looking for an effective way to do this that will last the longest... maybe someone can explain to me how the ones in cars work and i can just use same concept...instead of buying new things just tap into car 12V source and wire up something to do to make the circuit work forever
thanks
Replies:
Posted By: tedmond
Date Posted: December 16, 2007 at 9:19 PM
u can go buy a flashing led @ radio shack that will work off a 9volt battery or een the 12v car battery itself. look for the post about flashing LED, there are maybe circuits u can build that will allow the function of flash or simply buy the flashing LED premade; just wire and thats it
Posted By: rwdbmwm3
Date Posted: December 17, 2007 at 9:29 AM
how long does it last though? thats the most important thing ....
i remember when my friend bought a muliple flashing led fake alarm thing..ran off a 1.5V battery, lasted 1 night......
Posted By: tedmond
Date Posted: December 17, 2007 at 9:10 PM
an LED has a lifespan of 10 000 hours of usage. If u were to run that off a 9 volt battery, it would sure as hell last u a long time. I remember using one before off the 9 volt and it lasted for 2 - 2 and ahalf years. if u used it off ur car battery, who knows when it would die out. LED draw very little current.
Posted By: rwdbmwm3
Date Posted: December 18, 2007 at 7:18 PM
tedmond wrote:
an LED has a lifespan of 10 000 hours of usage. If u were to run that off a 9 volt battery, it would sure as hell last u a long time. I remember using one before off the 9 volt and it lasted for 2 - 2 and ahalf years. if u used it off ur car battery, who knows when it would die out. LED draw very little current.
nono i dont mean the MTBF of the LED .. i mean how long will it last when hooked up to the battery...
Like i said, my friend bought a little led circuit thing that 5 led's went right to left... 1.5V battery drained over the course of the night
for example if i was using the 555 timer circuit, how long would the battery last me (constant use 24/7)
Posted By: rwdbmwm3
Date Posted: December 18, 2007 at 10:28 PM
rwdbmwm3 wrote:
tedmond wrote:
an LED has a lifespan of 10 000 hours of usage. If u were to run that off a 9 volt battery, it would sure as hell last u a long time. I remember using one before off the 9 volt and it lasted for 2 - 2 and ahalf years. if u used it off ur car battery, who knows when it would die out. LED draw very little current.
nono i dont mean the MTBF of the LED .. i mean how long will it last when hooked up to the battery...
Like i said, my friend bought a little led circuit thing that 5 led's went right to left... 1.5V battery drained over the course of the night
for example if i was using the 555 timer circuit, how long would the battery last me (constant use 24/7)
Also someone said "12.8 volts minus 3.2 volts equals 9.6v drop across the resistor. The current is 30 mA, so use Ohm's Law to figure out that Resistance = Volts divided by Amps. resistance = 9.6v / 0.03 amps resistance = 320 ohms." if you have 2leds is it 6.4/60ma? or 6.4/30ma or 3 leds.... 3.2/ what
Posted By: KPierson
Date Posted: December 20, 2007 at 9:26 AM
You should be able to find some LEDs that pull less then 5mA of current and are plenty bright enough for what you are using it for. 5mA will lasts for weeks on a standard car battery. Of course, the longer the off time compared to the on time the longer the battery will last. Most aftermarket alarms don't have a 50/50 on/off time, more like 75% off and 25% on. This extends battery life quite a bit. OEM LEDs can be 10:1 or even higher for minimal current consumption. You can get a 555 timer and a few other components and make a pretty decent flashing circuit. You can then tap the igntion lead for ground (most igntion systems rest at ground when key key is off) and hook it up to constant power. This will give you a control circuit that will only flash the LED when the key is off. If you want to get a bit more sophisticated you can program a microcontroller to turn on and off based on lock and unlock pulses that will completly mimic an OEM or even aftermarket LED. ------------- Kevin Pierson
Posted By: mystic knight
Date Posted: December 23, 2007 at 10:57 PM
I'm not sure why you're planning on running it off a battery. If it's going into a car you may want to consider using one of the 3 wire Varad led's and wiring it to the car. Then it'll be running off the car battery. Having a little flashing light in your car even when your driving would probably get pretty annoying. And if you wired in a switch you'd always have to make sure you turned it on and off. https:////VARAD-LL-RE-SUPER-BRIGHT-RED-FLASHING-LED-for-ALARM_W0QQitemZ170179480396QQihZ007QQcategoryZ33713QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
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