If you check the modern cars, driving on our streets, you will realize that they all have a Day-Drive-Light with LEDs.
The critics mean, if everyone drives with light during the day, we survey the cyclists, because they only turn on their light, if it gets dark!
Ok, nice point. We bikers need bright enviroment-friendly light, too Hm, we all like LEDs! (You do, i´m sure ^^ ) LEDs on our bikes! Great idea!
So, I thought "Why, don´t build a LED-Bike-Day-Drive-Light?".

I started "developing" 6 months ago and realized that it is relative easy to do!
I wanted a light, that is bright enough to be seen on daylight.
In addition it should be possible to turn on both "light-systems" (the main-system: front-light, and rear-light, I hope you got them, but it is not necessary for this Instructable; and the new day-light-system)
And the most important point: it have to use the dynamo and NO BATTERIES.
Here on instructables.com are a lot of these battery lights, but if you ask me we all should never use batteries for a bike light! We have only the one planet... And we all should realize that good (longlasting) batteries aren´t cheap on long time. So, hey! A (Hub-) Dynamo is the best way if you ride your bike often. In my opinion good Bikers make their light in an environmentally friendly manner!

So, here are the advantages of the
Day-Drive-Light...
... makes biking safer
... looks great, everyone is looking at you!
... you can turn on your ordinary light and the Day-Drive-Light
... LED-light makes fun!

Ok i wrote to much. LED´s start!

PS: please read the complete Instructable before you start. Some informations are necessary for the complete LED-Light :D

Step 1: What You Need:

What you need is here.
The Circuit is easy, so you don´t need a lot of parts. The main circuit is not my invention (but would be great ^^ ) if you are interested you can find the developer here (german page)

Tools:
Soldering Iron and equipment
Wires

Parts:
2x SCHOTTKY Diodes

2x Capacitors 2200µF/ 16V
(you can use caps from 16 V on, but it is better if they make more Volts)

Your HighPowerLEDs. I used "AVAGO MOONSTONE LEDs" partnumber is: ASMT-MW62-NFH00

- > Some information for your LED-selection:
Our Driving-Circuit drives the current of the Dynamo to (low-cost-) LED-friendly 300-320 mA.
If you want to build it like I did: You can use 4 0,5W LEDs (2x2 parallel and the two pairs in series)
But you can also use 1 W LEDs (if you do so, you have to connect each LED in series. A Dynamo is able to drive ca. 3 1W LEDs)

In Addition you need a Dynamo. A HUB-DYNAMO is perfect.
AND THAT IS ALL!
Sorry, if I don´t write how much it costs, because you can use desoldered material for the driver-circuit. The most expensive parts are the LEDs.

Step 2: Build the Driving-circuit

Now, we build the circuit.
Before you start you should search for a place, where you want to install the Circuit. If you got one build your circuit, but build it in a way you can install it later! I installed mine in the bar of the steering-weel and secured it with a Cap i found in a toy.
I hope you can install your Circuit in the same way i did. It is the perfect place!
Pictures say more than 1000 words...
( Ohh, an old but true saying... xD)

Don´t connect the circuit-entry (the left site on the circuit-picture) with your dynamo now! (Read The "Really Important Information")
You have to connect the LEDs first!!!

- > REALLY IMPORTANT INFORMATION:
DON´T USE THE CIRCUIT IF NO LEDs ARE CONNECTED!!!
1. the Capacitors could be destroyed and
2. if you then reconnect the LEDs with the Circuit all the Current in the Capacitors destroys the LEDs suddenly !!
(If this is the problem; means you moved the wheel but have not connected LEDs, turn your Multimeter on the highest Voltage-Range and connect it with the Circuit on the LED-side, first. Then the Multimeter unloads the capacitors. After 5 Minutes you can connect the LEDs )

-> that means, if you want to use a switch, you have to connect it between the dynamo and the circuit and not between circuit and LEDs (But it is an Day-drive-light, isn´t it? Why to turn it off?)

Step 3: Install Your LEDs

OK, the most interesting step!

Now, I have to ask you: Where do you want your LEDs?
Left and Right of the Front-Wheel?
On your Steering-Wheel, like I did?
Or somewhere?
Try to find out!
The important point is: The circuit delivers ca. 300 mA. You know, that LEDs don´t "work" with voltage but with current. The Voltage adjusts itself then.

That means:
...your LEDs should have Specs of 300 mA (350mA) if you drive them (up to three) in series.
OR
...your LEDs should have Specs of 150 ma if you make 2 pairs of 2 parallel-connected LEDs and the Pairs connected in series. (I used this way)

If you did, install them and solder the Wires to the Circuit-exit (the right side of the circuit).

I protected the LEDs with transparent Lacquer against water. Then I made two Housings. They break the light and protect the LEDs, too.
On the pictures can you see them.

Step 4: Finish

Ok now we got the circuit and the LEDs. You have connected them to the circuit.
That´s all we need!
Last Step: Connect the Circuit to your Dynamo.

Ready?

Wohhaa we got the LED-bike-day-drive-light!!

Now you can ride your bike with wonderfull bright LED-light! Your friends will like it.
I hope it was a fun for you to read and build this.
If you like it, please vote for me.

See you on the street.
Led the sun shine!!