The circuit schematic is so simple. Just one resistor and a white LED.
Make it only for Rs.7and with a old USB cable.
LED (Light Emitting Diode)
The long wire is the positive. The short one is the negative.
100 ohms resistor
We should use a resistor because we don't want to burn the led.
USB cable
You need a old USB cable from a camera or from any other device
Here is the wiring diagram The USB cable have 5 wires. Two are for data and two are for power. If there is a extra wire, then it is grounded shield.
The black is negative and red is positive. The voltage from a USB cable is 5 volts.
The maximum current for any device connected to the USB cannot be more than 500mA.
How much current does this project use? it uses only 15.27 mA using a 100 ohms resistor. It is not a problem for the USB port. Using a 200 ohms resistor,the circuit uses only 8 mA.
Be careful that there are no short circuits. Do the wiring neatly
Attach a paperclip to the led so that it allows you to use it at the computer. Another way to attach is using a velcro It works perfectly and I can see the keys on my keyboard without problems. I can work at night without turning the light on. I even can read with this light.
