I'm not sure if this is right site for this, but couldn't find better.

I've been given an task to create something that has light intensity like police beacon. I need it to be cheap, so I'm looking at dealextreme.com LED emitters , but there aren't any good user experience videos.

I don't know if the LEDs are right for this and how should I pick right one from these LEDs.

  • 2
    \$\begingroup\$ Do you need it to flash ? \$\endgroup\$ – Rocketmagnet Sep 15 '12 at 22:33
  • \$\begingroup\$ Do you need a spot light, or what is commonly referred to in the US as a "light bar." \$\endgroup\$ – rdivilbiss Sep 15 '12 at 23:05

Maximising brightness:

Brightness is a function of amount of light and area illuminated.

  • More light = more brightness.

  • Less area = more brightness.


For more light obtain as many lumens as you can afford.

For less illuminated area use LEDs with low "radiation angle" or "cone angle".


If that is not bright enough you can use a lens or reflector.
Many companies provide lenses for LEDs.
Deal Extreme have a range here

Effect of colour: Note also that brightness is related to eye response to colour - yukky yellow green is about the best colour for optimum eye perceived brightness - but if you want a specific colour this is not much help in optimising brightness.

Related: Mind plasticity add on for the ever young:

Lime Green is close - Lime Green Fire Engine from here - BUT more recent studies suggest that familiarity is more important than visibility for emergency vehicles.

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  • \$\begingroup\$ Ahh, but why does the lime green fire engine have red lights atop it then? ;-) \$\endgroup\$ – Oli Glaser Sep 15 '12 at 22:03
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    \$\begingroup\$ @OliGlaser Because they got laughed at for for the teal and fuschia lights. \$\endgroup\$ – user3624 Sep 15 '12 at 22:22
  • \$\begingroup\$ What's all this about fire engines? I thought the guy just wanted to flash some really bright LEDs? \$\endgroup\$ – Rocketmagnet Sep 15 '12 at 22:33
  • \$\begingroup\$ @Rocketmagnet - The Feuerwehrwagen was a bonus - aimed at assisting bouncy fun smart and stretchy mental plasticity in aging brains. He said he wanted a bright light "like a police beacon" that may also mean he wanted red or just possibly blue - but maybe not. I mentioned that spectral frequency (aka colour) affects visibility, said that yukky green was about optimum and then decided that a lime green fore engine would help reinforce the point. Seemed like a plan at the time. \$\endgroup\$ – Russell McMahon Sep 16 '12 at 0:12
  • \$\begingroup\$ Yes, but where's the bit where you explain how to select an LED, how to wire it up, and possibly, how to make it flash? I can see a down vote coming... \$\endgroup\$ – Rocketmagnet Sep 16 '12 at 0:22

It sounds like you would be better of with an of the shelf high-brigtness LED lamp rather than individual LEDs for which you need to make a circuit.


If you want very high brightness for a split second, then a few seconds to charge it up again, use a camera flash with a timer circuit and a relay. It is really bright and is great for a lightning effegt


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