I'd like to have a blinking light that will look like it might be a security system but really is just a flashing light. Has anyone seen something like this? I'd love to have it run off a watch battery or something like that (or even be solar powered!), rather than have it hard-wired.

Any thoughts?

 

easy thing to do. I know there are pre-built packages but i couldnt tell you where you where to get one or how much they would cost. If you have some basic wiring skills and can solder the easiest (and probably cheapest) way to get what you want is to run down to radioshack, pick up a flashing LED (probably 2-3 bucks) and a battery holder (use a AA holder for small size since LEDs dont draw much power). You will have to read the specs on the LED to determine how many batteries you will need, 1.2-1.5V 1 battery, 1.6-3V 2 batteries. Next step is critical or you will fry the LED. If the voltage rating on the LED is not a whole number mulitple of 1.5V (typical AA voltage) you will need to wire an inline resistor to sap off the extra power. To figure out what size resistor you need use this formula:

R=V/I

where R is the resistor value in ohms, V is the total voltage of all batteries minus the voltage of the LED, and I is the current draw of the LED in amps (typically LEDs draw 20mA=.02A). I added an example calculation at the bottom of this for you in case you werent able to follow all that. Wire the resistor (these arent directional) to the negative lead of the LED (these are directional). If your not sure which side is negative, plug it into your battery and see if it lights up, if not, switch the leads and try again. Do this quick though or youll burn the LED and have to buy a new one. Once you have everything wired drop in your batteries and see if it works. If it does your set, find a place to stick the LED so its visible and tuck everything else away. If it doesnt work, check your connections and your polarity. If it still doesnt work, pm me and ill try to walk you through it better. Good luck!

typical LED specs:
forward voltage: 2v
current draw: 20mA

requires 2 AA batteries for full brightness
2*1.5V=3V

resistor needed:
R=V/I
R=(3-2)/.02=1/.02=50

resistor must be 50ohms or higher standard 51ohm resistor will work fine

 

That's an awesome how-to! You have clearly forgotten more about electronics than I will ever hope to remember in my lifetime. I'm going to save you instructions for further reference.

I think that my short-term solution will probably be something like...

http://www.defensedevices.com/fakautalflas.html

A bit cheesy, but the price is nice -- and the install procedure is appropriate to my skill level.

 

Here is a cheap route to take the next time you are in the grocery or drug store:

Quite a few products come in packaging that includes a red flashing LED to catch your eye and differentiate their product from the others on the shelves. If that particular product is something you can use, buy it and take apart the packaging to get to the flasher. It's commonly a small circuit board with a coin-type battery or two, a chip and an LED. Here is your 'fake alarm' warning. If need be, you can unsolder the LED from the little PC board and extend it with wires to make mounting easier. The battery generally lasts a few month of continuous flashing; you can add a switch to the circuit to turn it off and save the battery if need be.

You now have both a decoy alarm and most likely a big bottle of multivitamins.

 

Most LEDs comercially available are 3.3v, take 2 AA's to run (10% less than max brightness, but who cares), or you can slap a 800ohm on it and wire it into a +12v constant and a +12v switched (when the +12v switched is off, it goes to ground... and only has the LED flash when power is not on).

www.installer.com sells premade kits i think, or you can always call them and ask for big eddie, and he'll tell you how to make it if he doesnt sell it.

 

Just make sure you don't slap that ridiculous warning decal on your car - that screams "fake alarm"!

 

I'm telling you its amazing what you can find on eBay!

http://cgi.ebay.com/ebaymotors/ws/eB...hippingPayment

Maybe what your looking for or over the top?

 

I was going to do something like this w/ some 12v flashing LEDs I found on:
www.allelectronics.com They have a black bezel w/ 6' wire leads.
I was looking at putting them in the side turn signals.

 

The day after this thread started, I went ahead and ordered one of the fakeys online for about $7. It's functional, but I think I'll end up taking it apart and trying to integrate it somehow with the Euro Parcel Tray (perhaps in that notch piece, since I don't at this point have driving lights). Obviously, the trick will be to keep it somewhere visible.

And, yes, my $7 did include the cheesy "Steal Me" stickers. (That's not what they say, but that's what they say. )

Thanks, everyone, for the input!

[This whole thing got started, by the way, when I had a business meeting interrupted with a shrieking car alarm -- not mine. I thought to myself at the time, "I'd rather have my car stolen than listen to that $#@% for another second!" My hope is that the flashing LEDs will provide the preemptive visual impact without the auditory torture. ]

 

I did this a long time ago with a Radio Shack blinking LED with AA battery and mounted it into my Euro parcel shelf on the far left. It wasn't bright enough or visible enough to my liking.

Since then I have an aftermarket alarm that sounds if you touch my MINI.

Some links on making your own LED blinker.
http://lakeview.esu7.org/science/LED/flashing.html
http://www.qsl.net/yo5ofh/hobby%20ci...d_circuits.htm
http://wolfstone.halloweenhost.com/H...ngLEDEyes.html

 

Down in SoCal when 911s used to get stolen despite the latest Cliffords and Alpine alarms, we used to install blinking LEDs on the door panel next to the window. Attached it to a 9v battery and never had a problem.