Building an LED VU Meter: Wiring

What You'll Need
14 to 16 GA wire
Electrical tape

A VU meter is a device used in measuring the loudness and softness of the sound coming from a sound system. VU means Volume Unit. LED means Light emitting Diodes. It uses very little amount of electricity and do not produce too much heat. There are things that you need to consider when wiring LEDs. You need to carefully plan out your project to avoid damaging them. Listed below is an informed step by step guide on how to wire LEDs.

Step 1 – Plan it Out

LEDs like any light bulbs get damage in prolonged used, so you need to equip yourself with tools that will allow you to replace it in the future easily. One thing to remember when planning out your project is that you should never attach the LEDs straightforwardly into your project unless you will not be using it for a longer period. You need to get a disconnector to connect the 2 lead wires into the LEDs, place one disconnector to the LED and then get another one for the wire connecting to the power supply.

Step 2 – Power it Up

The electricity requirement for LEDs varies depending on type that you will be using. However, you need to adjust your electricity supply for different LEDs, because it will not light up if not supplied with enough electricity. Ask for assistance when purchasing the right LED voltage requirement. Here is the list of LEDs and its voltage requirement:

  • Orange and Red              - 2.0 V
  • True green, Blue, White   - 3.3 V
  • Yellow                            - 2.1 V
  • Green                            - 2.2 V
  • Blue (430nmn)               - 4.6 V

You just need to multiply the power requirement with the number of LEDs that you plan to use. For example, if you want to wire 5 Orange LED, just multiply 2 V to 5 = 10 V. You will then need to get a power source adequate to supply 10 V.

Step 3 – Calculate the Resistors Value

Get protection to cover the LEDs from damage. A resistor is perfect for the job because it lowers down the electric supply for the LEDs to not be damaged. However, there are various types of resistors available. To get the right type, you need to know the resistor value that will work best on your LED. Just follow this formula LED resistor value, R =(supply voltage – LED voltage) x LED current = R. If the manufacturer does not include the LED current, you may use the 20mA. However, you need to first check the correct LED current.

For the example above: R= (10V - 2 V) x 20mA = 120ohm. 120 is the minimum so you need to get a resistor that will work best for that current.

Step 5 – Tape it Up

Tape up the exposed wiring or metals to avoid electrical shock which can be a cause of LED malfunction. Use an electrical tape when doing this.

Step 6 – Connect the LED

The LEDs must be connected in series. The wiring should always be positive wire to negative wire. You add up as much LEDs as you want and colors as you want, but be sure to calculate the power requirement and the resistor value for your project to work well.