Whether for business or novelty, LED signs are relatively cheap to produce compared to neon signs. The popularity of LEDs has driven down the cost considerably, and the rainbow of colours available permits more creativity with the design. Another advantage of using LEDs is low power consumption when compared to neon tubes and especially incandescent bulbs. Some basic handy skills and a few hours are needed to create your own LED sign. This project will also require some basic knowledge of electronic circuits and the characteristics of the individual components.
Lay out the design for the sign. Using a pencil, mark on the sign board material where the centre of an LED will poke through it.
Make holes for the LEDs. Using a drill and a drill bit that is smaller than the LED diameter, place pilot holes through the sign board material where necessary. Follow these holes with a drill bit that is equal to the diameter of the LED.
Insert the LEDs. From the back side of the sign board material, poke the LEDs through to the other side. The LEDs must remain in the sign board material. You can apply a small dab of a multi-purpose adhesive to the LEDs on the back side of the sign to keep them in place. If you use an adhesive, find one that won't damage the plastic LED packaging.
Determine the circuit that will provide the desired result. Use an online calculator to determine how your schematic will look. For calculation purposes, your LED voltage drop should be somewhere between 1.4 and 1.8 Volts, depending on the LEDs you have chosen. A forward current of 20 Milliamps is usually sufficient. You will have to calculate a different circuit for each type and colour of LED.
Select the appropriate value of resistors needed. The circuit you designed with the online calculator will determine the amount of resistance you need in each part of the circuit. A resistor band colour chart will make selecting these resistors a lot easier if you don't have the colour scheme memorised.
Warm up the soldering iron. Plug the soldering iron into an electrical socket and let it heat to a temperature sufficient to melt solder. Touch a piece of solder to the tip of the iron once it has been plugged in for a few minutes. If the tip is hot enough, the solder will melt on contact. Otherwise wait a few more minutes and check again.
Determine which LEDs will connect to the power supply. The longest end of an LED is the positive lead. Bend the leads appropriately to touch each other and solder them in place with the core solder and the soldering iron. If two leads cannot reach each other by bending, use a wire cutter and a wire stripper to create an appropriate length of 22 AWG solid wire and solder it between them.
Solder the appropriate LEDs in series. Determine which LEDs will make up which parts of the circuit. The negative lead of each LED in the previous step should now be soldered to the positive lead of another LED for that portion of the circuit. If there are more than two LEDs in a portion of the circuit, solder them in the same way so that only negative leads need to be connected to resistors in the next step.
Add the resistors to the circuit. Solder one end of each resistor to the remaining negative lead of an LED. Solder together the remaining ends of each resistor to complete each leg of the circuit.
Connect the power supply to the sign. Using the wire strippers, remove enough of the insulation jacket on both positive and negative wires. Solder each to their respective end of the circuit.
Test the LED sign. Plug the DC power supply into an electric socket and turn on the sign. Verify that all LEDs are lit.
Using 1/2 Watt resistors helps protect the circuit from any spikes in current that may occur.
Consider putting a frame around the sign for a clean, professional look.
Make sure that the calculated wattage needed for your sign is less than the maximum power output rating that is on your power supply.
Wear safety glasses while soldering.
Wash your hands thoroughly before eating, drinking or smoking to avoid lead poisoning.