Overview

This simple USB powered LED lighting system provides portable lighting which can be used for different purposes such as when the lights go out, during emergencies, as a desk lamp, outdoor lamp, etc.

Details

The lamp uses 16 white 5mm LEDs connected in parallel to provide lighting. It was designed to be powered from a 5v source such as a power bank or from the USB port of a laptop.

A 10ohm resistor is placed between the positive power supply and the LEDs to limit the current flowing though each LED to about 17mA which is good enough.

Components Needed

  • A piece of perfboard
  • 1 10ohm resistor
  • 16 white LEDs
  • 1 Barrel jack
  • 1 Barrel jack (female)
  • Jumpers
  • A USB cable
all components

Components used

Tools Needed

  • Soldering iron
  • Soldering lead (this isn’t really a tool though :D)
  • Desoldering pump (Not required but may come in handy)
  • Wire Stripper or plier

Circuit Diagram

fritzing-schematic

Fritzing schematic

Building the Circuit

1. Arrange the LEDs on the perf board in a 4 by 4 grid. Make sure the terminals/legs of the LEDs facing the same direction. Check this tutorial on LEDs or this tutorial on how to use a perf board if you need help

led-array

led array

2. Solder all LEDs in place, but first be sure to test with a multimeter to make sure the LEDs are working. You can check out my tutorial on how to use multimeters.

soldering-leds

Soldering LEDs

3. Connect all positive terminals together using the jumpers and repeat the same procedure for all negative terminals

connecting-terminals

4. Solder the power jack in place.

soldering-powerjack

Soldering Power Jack

5. Connect negative terminals of LEDs to negative terminal of power jack with a jumper

negative-terminal-to-power-supply

Negative Terminal of LED to power supply

6. Solder the 10ohm resistor between the positive terminal of the barrel jack and the positive terminals of the LED

soldering-powerjack

10ohm resistor

7. Cut the smaller end of the USB cable to reveal the 4 wires. We are only going to use red and black. Solder them to the male barrel jack as shown below. Red wire goes to the center pin. Black wire goes to the outer pin. Center pin is the shorter terminal.

powercable

Power cable

powercable

Now you are done. Plug one end of the USB into the LED panel and the other end into a power bank or PC.

finalassembly

final assembly

Often with electronics circuits, there is a pretty good chance your circuit may not work on first try and you may have to probe it to see whats wrong.

If all goes well, your LEDs should light up like mine. If it doesn’t

  • ┬áCheck for loose soldering joints
  • Try switching the position of the black and red cables you soldered to the barrel jack. (you may need a desoldering pump for this)
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