DIY backlight for analog meter.

Another example of successful implementation of a method of making custom backlight that was described in details in previous post.

In this project I added two color backlight with separated control to vintage analog meter.
Blue light serves for improving visibility of dial in the dark and for aesthetic purpose. 
Red light can be used as a warning signal, to indicate that measured value has reached predefined limit.  
Blue and red  LED circuits are powered by two separated 5V sources.  

DIY multicolor backlight for analog meter.

This project is very simple, cheap and novice friendly but may result in quite impressive mod of some piece of obsolete hardware.

Parts and materials used in project:
 - ancient analog voltmeter;
 - 3 mm red and 10 mm blue LEDs;
 - resistors;
 - wires;
 - breadboard;
 - piece of acrylic.



Red backlight is made by well proven method: 3 mm red LEDs embedded into sides of light emitting panel.
Panel is made from piece of 1/8"clear acrylic.
Front side is sanded to diffuse light and back side is painted white to provide soft and even light reflection.
LEDs are filed to form squire shape and glued into notches cut in sides of light emitting panel. 

Red backlight.

Panel is hot glued to the back side of meter dial.
Each LED is connected in series with current limiting resistor.  
Resistor and exposed bare wire are protected with heat shrinking tube.

Light emitting panel mounted on a back side of dial. 

Nice effect of relaxing ambient light is achieved by using 10 mm super bright blue LEDs.
LEDs are sanded with fine grit sandpaper to diffuse light and create soft illumination.

Blue LED for ambient light.

LEDs and current limited resistors are mounted on two pieces of breadboard.

Blue LEDs mounted on breadboard.