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A Short Story About These LED's

These LED's came from a warm white led tube which is made up of a SMD PCB strip inside a protection tube.

Right at that time, Our building decided to replace all of the fluorescent lights in our underground parking lot with LED tubes (These look exactly like fluorescent bulbs, But are more efficient and live longer), While installing the lights, One of them broke. Later that day, I found the broken bulb in our garbage room, And I knew it would be perfect because it had exactly the LED's that I needed for my project!

There will be pictures of the light while on, But sadly, My camera can't express the terrifically high lumen output and the "beauty" of the daylight colored LED's...

If you're interested in understanding more of what these led fluorescent replacements are, You can see more pictures of these link to Google Images.

And, If you're interested in buying these high efficiency led tubes you can get them here on eBay.

Step 1: Starting the Build

As you can see in the picture and maybe recognize, This was made out of a car windshield mount for a phone.

In the beginning I modified the phone mount so it could be a tripod, But it turned out pretty bad so I never used it again.

A couple months later, Well this was my idea...

Step 2: Power Supply Decision

All of the LED's on the strip are connected in series.

For powering the 1 LED I need 3 VOLTS, For 2 LED's I need 6 VOLTS, For 3 LED's I need 9 Volts, This goes on, and on, and on...

I had two options to power them:

A 12 VOLT power supply

Or A 20 VOLT power supply (From a laptop computer)

Powering With:

12 VOLTS: This means I need 4 LED's.

20 VOLTS: The closest possible is 7 LED's.

7 LED's obviously need 21 VOLTS, But 20 VOLTS meant that each led gets 2.85 instead of 3 VOLTS which is okay.


The reason I chose 20V and not 12V was because I really wanted to use this specific high quality heat-sink. If I used 12 VOLTS I would need to put the LED's in rows of 4 which would waste more space on the heat-sink (meaning less light) and I would need to buy a high AMP power supply because of the lower voltage. Another reason I chose 20 VOLTS was because I wanted to be able to have an option for adding more LED's In the future.


By the way, The whole strip itself has 90 LED's which all together uses 18 watts, That means each led draws about 0.2 WATTS.

Link for a 20V 4.5A Power Supply (eBay)

I don't need 4.5 AMPS, That's just the power supply I had, And except for the fact that the 4.5 AMPS power Supply Is a bit bigger than a 12 VOLT power supply doesn't really bother me.

Step 3: How I Connected the LED's

This part was really boring and took me a long time:

I scraped the plastic coating off the strip really carefully with a sharp utility knife to reveal the the insulated positive and the negative copper connections, so I could solder the connections after that.

Step 4: Soldering

As seen in the picture I soldered all of the strips in parallel so each strip would get 20 VOLTS (Not 2.85 VOLTS for each strip, Which would happen if I soldered the strips in series)

I also soldered a toggle switch in series from the power supply to the LED's.

Step 5: Epoxy

I glued the led strips to a flat aluminum piece using heat conductive epoxy to help cool down the LED's

Step 6: Hot Glue

After gluing the LED strips with epoxy to a thin piece of aluminum, I glued the aluminum plate to a heat-sink (I took apart from a desktop computer) And then hot glued the heat-sink to the phone mount.


DONE!!!!!!


If you are wondering what my overall cost for this project is, The answer is: NOTHING.

All of the parts I used are parts I already had!

Step 7: It Works!!!

I Promise you that if you make one like I did, It will be worth every second it took you to make it!

Step 8: Detachable

A couple weeks after finishing the project, I noticed by mistake that I could detach the flashlight and I could hold it in my hand which is really useful when I want to take a well lit picture of something (like an Instructables project)

Step 9: More Pictures

Step 10: What Do I Usually Use It for the Most?

  1. Regular Lighting: It's bright enough to light up my entire room
  2. Reading a book
  3. For Filming: Instructables projects, or random stuff.
  4. Projects: It Is really helpful for me while Soldering, Taking apart electronic devices, Building, And more!

There Isn't a day I don't use it!

Step 11: Thanks!

Wan't to see more projects like this? Don't forget to visit my Instructables page!

If you find a that I made a mistake please point it out so I can fix it

If you build a project that is similar to what I built, Please post a picture in the comments to show everyone!

I'd also really appreciate it if you vote for me in the contests I've entered :)

Thanks for watching :)

<p>To answer something you said below.</p><p>Voltage is what the power supply GIVES the article [led or motor or toaster etc etc].</p><p>Amperage is what the device TAKES from the power supply.</p><p>Over simplified but I hope it helps :)</p>
<p>Makes sense. Thanks.</p>
<p>You are very welcome :)</p>
<p style="color: black;">Hi,</p><p>Nice project, I just bought a 30W LED lamp yesterday, to mod it (to make it dim-able) for a work light as well - having too little light when working with small stuff is a pain :)</p><p>(Gotta remember to make a write up as I go along)</p><p><em>&quot;</em><em>If you find a that I made a mistake please point it out so I can fix it&quot;</em></p><p>It sounds strange that each LED should be happy with only 3.0V, as white LEDs usually has got a voltage drop of 3.4V to 3.6V.</p><p>Whatever the actual drop is for your LEDs, you're feeding them too much current, which will reduce their life severely. ~67mA if they're 3.0V devices and ~56mA if they're 3.6V - if they're regular LEDs, you should reduce that to ~20mA (which will decrease brightness a lot), or accept that overdriving them that much will make them fail prematurely. It doesn't seem that there's any current limiting resistors in place(?) either and LEDs <strong>must</strong> be current limited (you can't control them reliably via the voltage).</p>
<p>Thanks :)</p><p>I honestly have no idea about if I'm feeding the LED's too much current, I'll try to research it if that's possible</p><p>But don't the LED's take the exact amount of milliamps they need to work on?</p>
<p>Unfortunately not, they're suicidal in their craving for current, so we have to parent them a bit ;)</p><p>The easy way to determine their voltage drop is to take a single LED and connect it <strong>in series with</strong> a resistor (470 Ohm to 1 kOhm) and drive the combo with a 9V (PP3) battery. Then you can measure the voltage over the LED - this is probably around 3.5V or so.</p><p>To limit the current in the strings, you need at least 1V more than the combined voltage drop of the LEDs, so for a 20V supply, the LEDs should be 19V max. so, if your LEDs turn out to be, say, 3.43V, you can have 5, for a total of 17.15V, leaving (20-17.15) = 2.85V for the resistor.</p><p>For 20mA (standard current in most regular LEDs) you need a resistor of (2.85V/0.02A) = 142.5 Ohm.</p><p>Nearest standard values are 120 Ohm (giving 2.85V/120 Ohm) = 0.02375 A (23.75 mA), which is a little high, but not too bad.</p><p>Or 150 Ohm which gives you (2.85 V/150 Ohm) = 0.019 A (19mA), which will keep your LEDs in good shape for years to come.</p><p>Naturally, you won't get the same amount of light, so you may want to add more strings - and remember that each serial string needs its own resistor (LEDs don't like to share ;)</p><p>All the numbers above are just examples and you'll have to change them, according to the actual voltage drop of your LEDs, before calculating the resistor value you need.</p><p>If you need more guidance in finding the right resistors, we can take it step by step if you like :)</p>
<p>Sorry it took me about a billion years to reply,</p><p>So basically what I understood is that if I'm undervolting (is that even a word?...) them, they can't draw too much current...</p><p>Is this correct?</p>
<p>Thanks, I'll try it and see how it goes</p>
<p>You do not need 9 volts for 3 LED's. <br><br>You could put 3 led's in parallel, they would just drag more current.<br><br>50/50, lower voltage more current, more voltage lower current. <br><br>Same wattage. =)</p><p>But i understand you wanted to keep the strips as is, and rather use more voltage. :)</p>
Lower voltage= need to buy power supply<br>Need to buy power supply= I don't think 3.5 amp power supplies are even made :)

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Bio: 14 year old, sick with a deadly disease called DIY-itis!
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