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DIY moonlight for a 2ft tank


Z3n5f3r89
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Go sim lim and buy those super bright blue LEDs. They cost around a dollar each. get a DC power source (eg adaptor) with rating to support the LEDs (dont need very high, 500 mah more then enough) If using 12-15v dc just connect 4 LEDs in series and walla, let ther be light

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Go sim lim and buy those super bright blue LEDs. They cost around a dollar each. get a DC power source (eg adaptor) with rating to support the LEDs (dont need very high, 500 mah more then enough) If using 12-15v dc just connect 4 LEDs in series and walla, let ther be light

u get the bulb blown in no time........... ;) u need resistor.. :D

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1-3 should be enough if you're using it as a moon light for a two feet tank. Of course you can use more if you want it BRIGHT. You can use an acrylic diffuser to diffuse the light output or you can sand down the LED's len( the front part of the LED) to a flat or a V shape. Remember to polish the surface after sanding to prevent reduction of light output.

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how many ohm resistor to use?

But if you tame me, we shall need each other.

To me, you will be unique in all the world.

To you, I shall be unique in all the world...

You become responsible, forever, for what you have tamed.

-Antoine de Saint-Exupery

Keep our hobby sustainable, participate in fragging NOW

CHAETO Farmer FarmerDan.gif

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simple calculation

Assuming

1)The LED you have gotten has to be Fwd Biased at 1.4Vdc

2) Continuous Fwd Current - 20mA (Typical)

3) You are puting 3 LED in series.

4) AC/DC adaptor rating at max 12 Vdc (500mA)

----- These adaptors u can get easily at less then 10 bucks.

Soln

------

Vin

12Vdc- 3*1.4 Vdc

= 7.8Vdc

Contiuous Fwd Current - 20ma

Therefore to calculate for a current limiting Resistor

V=IR

R=V/I

= 7.8/0.02

= 390 Ohms

However, I think you can use any resistor value between 350 ~ 450 ohms, probably wouldnt make much difference since this is a relatively simple DIY.

**

The Resistor shld be placed in series with the 3 LEDs.

rgds

Silver

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:blink::blink::blink: I am stumped :blink::blink::blink:

But if you tame me, we shall need each other.

To me, you will be unique in all the world.

To you, I shall be unique in all the world...

You become responsible, forever, for what you have tamed.

-Antoine de Saint-Exupery

Keep our hobby sustainable, participate in fragging NOW

CHAETO Farmer FarmerDan.gif

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  • 2 weeks later...

Sorry to ask, with a AC to DC adapter(max 350ma) with variable knob to adjust to the desire volts, Should I choose 3Vdc, cause I have acquire 6 LEDs with working 3Vdc and drawing 15ma. So what resistor should I use when I place the 6 LED in parallel? Pls help.

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The formula given earlier is very clear:

Soln

------

Vin

12Vdc- 3*1.4 Vdc

= 7.8Vdc

Contiuous Fwd Current - 20ma

Therefore to calculate for a current limiting Resistor

V=IR

R=V/I

= 7.8/0.02

= 390 Ohms

However, I think you can use any resistor value between 350 ~ 450 ohms, probably wouldnt make much difference since this is a relatively simple DIY.

]

If you put them all in parallel, you will only have one voltage drop of 3Vdc, but you need 6 times the current as it will be equally split between all the LEDs so you need an different limiting resistance:

12VDC - 3Vdc= 9Vdc

Total current needed: 6x 0.015= 0.09A

9Vdc/0.09= 100 ohms minumum (more is safer, but brightness will not be max)

put one resistance in series with 6 LEDs in parallel

To reduce current consumption you can cable two times 3 LEDs in series:

12VDc- (3x 3VDC)= 3VDC

3VCD/ (2x0.015)= 100 Ohms (same in this case :P )

I hope this helps

Cheers

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Still cannot find :(

Can someone tell me where can get and wat the shop name.i went the shop name is Sinter electrical company at #03-05.There no 4th floor.4th floor is car park aready.No 1 hear of moonlight b4.Some one even tell me Sun light(the shop name)have....Aunty.Do they sell full set?Cause i donno how to do.Or is there someone that can help me...i plan to do b4 chinese new year. :nc:

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Go farnell and buy.

Either self-collect for ask for delivery, pay with credit card.

You're quite near when you're at Sinter.

Walk out from sinter, turn right then walk straight then you should be able to see the shop the sells the LED on your right.

Tell them you want super bright LED and not moonlight :P

Hmm... I thought LEDs are easily avaliable everywhere in Sim Lim tower?

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