The High Power USB Led Lamp

Hello everyone. I'm a mechanical engineer and Led emitter is one of my favourites. In this instructable I just want to share with you how to make our own USB led lamp with many options.

In this simple version, I make a table lamp with few parts.
1. Cree emitter XML T6 or U2, www.cree.com/products/pdf/xlampxm-l.pdf
2. Old CPU heat sink, thermal compound and thermal glue or GP silicon to fix the led emitter to heat sink.
3. Two antenna rods from old lamp, you can use a  mini camera tripod
4. A metal base and 2 screws, washers to fix these rod to the base, the lamp base can be plastic or wood.
5. A  normal USB cable, electric tape and 2 pieces of plastic for isolation.

The heigh and the angle  of the lamp can be adjustable. With one led, the lamp can light at  600-700lm and 6W.

Since this is very simple one, I just describe as below:
1. Fix the led to the heat sink.
We can just glue down the stars using silicone glue by "GE Silicone-2" as our  Dan Goldwater in https://www.instructables.com/id/RGB-Color-Controllable-High-Power-LED-Room-%2b-Spot-/step8/attach-LEDs-to-the-heatsink/ . I use Noctua thermal compound between led and CPU heat sink then a drop of glue. It also work great and reliable.
2. Solder the led to the cables.
3. Connect the cable to the antenna rods.
4. Insert 2 pieces of plastic for isolation and fit to the heat sink.
5. Use screw, washers to fix the rods to the base, remember to use plastic washer and electric tape for isolating one rod ( positive rod) that will be connect to the positive wire of USB cable.
6. Connect the rod to the USB cable, red wire to the positive rod and black wire to the negative rod. Please refer to http://pinouts.ru/Slots/USB_pinout.shtml if needed. Short the 2 data lines together.
7. Pull the rod to make the lamp highest then plug to the USB port in your computer.

 With this version, we can plug to any USB port of mobile device charger with 5V voltage  and current range from 0.7 up to 2A (for Ipad)

Estimate calculation:
Our led will work with forward voltage about 3.1 V and current 1.8A, we need to maintain the  computer USB voltage at 4.75 then we need a resistor to consume 4.75-3.1=1.65 V and the value is 1.8/1.65=1.1ohm.

In this case,  the total resist of the USB cable wire, rods( at the longest position), wires (from rods to the led) is 3 ohm and the lamp work very well.

When we shorten the antenna rod, these work like a Rheostat and in case the total resist from led emitter to the USB port is less than about 1.1 ohm, the lamp will start flashing. To prevent this, we add a resistor.
Depend on the lowest resistance value of the rods, we can calculate to add a resistor with value up to several ohm if you want. In this step, 0.22ohm, 2w should be used. We can use a 5A diode with forward voltage about 0.3-0.5 V.

We can also add a  mutil-position switch, in this case I use 3 position switch, first position for High with R=0, the second position for Off and the third position for Low with 0.22ohm resistor.

Depend on the lowest resistance value of the rods, we can calculate to add a resistor with value up to several ohm if you want. In this step, 0.22ohm, 2w should be used. We can use a 5A diode with forward voltage about 0.3-0.5 V.
We can also add a  switch, in this case I use 3 positions switch, first position for High with R=0, the second position for Off and the third position for Low with 0.22ohm resistor.

In this version we use a flash light driver, for example: http://www.dealextreme.com/p/5-mode-led-driver-circuit-board-for-flashlight-dc-2-8-4-2v-106796

To reduce lost power, we make the cable as short as possible and we can also detach the CPU heat sink.
 We now drill 2 holes with  2mm diameter and put 2 cables from Led through them. Connect these cable to the led driver.
We also add a USB port to the led driver and battery as the picture. Use magnet as battery holder.

This is quite similar to version 4 but we put the led driver to the battery holder.
We can use a bottle as the lamp stand.
In case we don't want to use the bottle, we can use the colour plastic spoon as the pictures.

Any recommend is highly appreciated. Thank you.