Picture of Retrofitting LEDs in a Dynamo Bulb
Hello , again ,

As you know there are several instructables on building Bike Lighting systems ,but , hey i wanted to post my own .

After a couple of hours searching instructables ,I haven't saw a proper Bulb-Led conversion , i've just saw some spam or ones with incomplete instructions .

Now i will show you how to retrofit an LED array into a Regular Light bulb , which i think is brighter cleaner , and lotsa times cooler .

As a Bonus i used this LED array in my Bike's Dynamo, Voila, Much more output and half the Power .
Remove these adsRemove these ads by Signing Up

Step 1: Materials 'N' Tools

Picture of Materials  'N'  Tools
For my Array I used 3 LEDs but you can use up to 5 (well you can really use more , but there is not enough space...)

The List:

3-5 White Ultra-Bright LEDs (mine were 4900mcd)
1 Used, Burnt or Spare Screw-type Bulb
5-10 CMs(2-5inches)of Small Gauge Wire (mine came from an IDE cable,which is 26AWG)
1 Small Piece of Scrap circuit board (mine had a Dotted design,which is pretty Common)

-The Usual Soldering Equipment ( Soldering iron , Solder , Helping Hands, Sponge ,Etc)
-Needle or fine tipped Pliers (mine are rusty, That's Why i used my Multi-tool)
-Small Cutters
-A round file
-Hobby knife (i used A hobbico body and a X-acto blade)
-Hot glue and hot glue gun
(Not shown but handy to have )
-A fine tipped Permanent marker
-6 Volt supply and alligator clips
-A Small alligator clip

Step 2: Some Notes About LEDs

Picture of Some Notes About LEDs
(thanks for the suggestions , PKM , Killerjackalope,and AndyGadget)

Our LED array should be Arranged in Parallel , it means LEDs should share positive and Negative Rails .

LEDs are diodes by themselves , so the need for A bridge rectifier is almost unnecesary , yet you
can put one if desired .

The Specs of my LEDs are
Forward Voltage 3.2 - 3.8 Volts
Average Current 25mA
And mcd is 4900

Step 3: Crack that sucker !

Picture of Crack that sucker !
This step can be a little messy and/or Dangerous ,
You've heard right DANGEROUS , i'm not liable if a small shard of glass poke one of your eyes

Remember to remove the solder from the nipple(if it's called like that...)and from the side .

The Safe Method to Remove the old bulb , consist of wrapping the Bulb in A piece of paper and cracking it with the Pliers.

My bulb was loose so it came out by just pulling it gently .

Step 4: Clean that sucker !

Picture of Clean that sucker !
Using the round file , and the X-acto Knife , The result will be a clean inside bulb-less base , (and a small pile of a cement Residue , it is not toxic , but you shouldn't eat or lick it , is nasty!)

Step 5: Plan Your Array

Picture of Plan Your Array
Figure out how to form a Triangle-like figure (or square or pentagon...) using the LEDs

Then, draw the outline of the base using the Marker ,

And at Last but not at least cut the board trying to adopt the shape of the base as much as you can ,
When done , Dry fit the board and the LEDs

It is pretty Straight-forward , you may also use the pictures as reference

Step 6: Soldering those LEDs !

Picture of Soldering those LEDs !
I think this is self explanatory , be careful not to burn yourself

Solder all the leads to the board

(in case you Ask , i decided to solder each LED one by one)

Step 7: Anode with Anode

Picture of Anode with Anode
This step is also Fast

You need to join electrically the three positive leads , just bridge them with solder .

When done, dry fit the array in the bulb base

Step 8: Common Anode to Wire

Picture of Common Anode to Wire
wiyah 2 .006.jpg
This is when that little wire comes in , cut a small 2.5 cm (1Inch)piece of wire , strip it and tin it with solder , do this same process in the other side.

Now is time to cut off the Leads of the Common Anode .

When Done , solder one of the sides of this little wire to the common Anode(positive) of the Array.

Both Pictures have Photonotes , that can be used as reference

Step 9: Wiring the Ground

Picture of Wiring the Ground
This is also an easy step

Clip the cathode leads , Then apply a little bit more of solder

Now , Strip about 1 and a half (1.5)inch of wire , twist it gently , and tin it ,

Proceed to wire all the ground together , making a kind of loop , when done ,
cut the excess wire .

Now is when the PSU comes in , Give the array a try , you know you want to !

Step 10: Wirin' it all

Picture of Wirin' it all
This step consists of soldering the Positive wire to the nipple of the base

Then clipping off the excess of wire.

The picture make this step pretty straight-forward

Step 11: Gluin' it down

Picture of Gluin' it down
Using hot glue (and gun) fill the base with glue , than quickly putting down the
array taking care that the Ground loop touches the body of the base .

let it harden for 15 minutes , and give a final test , Congratulations

You have finished your new LED bulb

Step 12: Final thoughts , A note about Resistors And things that just didn't fit into another step

Picture of Final thoughts , A note about Resistors And things that just didn't fit into another step
As you can see this array is reliable , shockproof and it will not burn in a loooooong time ,

I just have a single test Picture since where i live is raining , but believe is as bright (or more!)
than the Original bulb .

Yes , i know that there are several more powerful LEDs in the market , but I was too lazy
to wait 2 weeks of shipping, so i went to my local surplus store and bought them , you may also
salvage the LEDs from a toy or a Chinese flashlight , or better , order them online .

About Resistors :

As most of you know LEDs must have a Current limiting resistor to prevent burning

MATH time , yay!:

5.9 volts of the dynamo minus 3.3 of the LEDs is 2.6
2.6V divided by 0.075A = about 35 ohms (thanks PKM!),the neares safe value is 33

So I just soldered a 1/2 watt 33 ohm resistor in series to the array , I haven't suffered any
disgrace so i think is pretty much OK ,

Resistor color code is orange orange black gold

Anything you need : if you have questions , suggestions , mods feel free to put a comment
or PM me

Thanks , Lots of thanks , for watching ,analising ,doing ,modifying commenting and whatever-ing you
do with this Instructable . Perhaps destroying it ?

If you liked it , please rate or better vote for me in the Let it Glow! contest

Thanks a lot

see you next time