MINI MOOD LIGHT
Home > Group Projects > Mood Light Project
UPDATED:.22:34 22 October 2013

INTRODUCTION:

It has really been only recently that high brightness LED's have become cheap enough and powerful enough to produce adequate lighting from low voltage. Two LEDs available from Kingbright are cheap and bright enough to enable this creative project.

This project uses 2 multicolour LED's and a PIC to produce an ever changing light source powerful enough to illuminate clear acrylic and light a darkened room.

(The video, left, does not do the colours justice!).

PLEASE NOTE: The PIC IC used must be programmed with a program to provide the PWM control over the LEDs.
This pre-programmed IC can be obtained from our shop.

CIRCUIT DESCRIPTION

It works from 2 LED's that have red/green and red/blue colours. The intensities are impressive (shown below) and the whole circuit works from 3 x AA batteries. Rechargeables are ideal even with the slight voltage loss (to about 3.8v).

The circuit is very basic thanks to the PIC IC. R1 and C1 form a start-up reset signal for the IC and C2 decouples the supply. The remainder of the circuit is four resistors and LED's. There are 2 red LED segments to light meaning four outputs are needed since the max output current of any pin is 25mA.

Most of the projects used 8mm acrylic drawn on 2D design package and then cut and etched using a laser cutter.

Some chose to use "light-gathering" acrylic rod combined with a simple acrylic shape and produced some really unique designs.
Some of the rods were heated in an oven and twisted around steel rods - gloves were used!! These were inserted into 8mm acrylic to act as a holder.

CONSTRUCTION

This can be broken down into the following sections:

  • Laser Cut Acrylic/Acrylic shapes
  • Circuit board construction
  • Vacuum formed cover
  • Fitting and wiring together.

ASSEMBLY:

Below is a view of how everything fits together. The only precise part is lining up as much as possible the LEDs on the PCB with the slot cut in the case.

ACRYLIC

Clear 8mm acrylic was laser etched and cut to produce the final figures and shapes.

Images from the internet were converted to black and white images and then contoured all using 2D-design software.
A
drilling jig was used to drill the 2 5mm holes in the end of the acrylic.

Battery pack dimensions:. W = 50mm, L = 60mm, H = 18mm
Circuit board dimensions: W = 30mm, L = 45mm, H = 15mm

Download wiring diagram - PPT.

PCB LAYOUT:

Below is a image of the LED's that are used. both look identical unfortunately. The shortest leg, also the flat side (normally denoting the cathode) is the red segment on each LED. The middle leg is the cathode, the shorter leg is either green or blue

The PCB contains a total of 8 components. Pretty straight forward really.


PCB size - 45x30mm

VACUUM FORMING THE COVER:
The covers were embossed with a relief shape or figure that had a connection with the main acrylic design.

The one shown was a mouse cut from 4mm MDF using a hegna saw - this was cut by a Year 9 student!

The waste area was removed with a Gerbil cutter and sanded smooth.

A 6mm MDF base was shaped using the mould as a template and a sharp pencil.

The slot in the case was also cut with the laser cutter - so handy! However it can be drilled out and filed.

It is very important to assemble PCB and battery holder to the base before cutting the slot. The is limited room for adjustment with the base parts.

When drilling the holes in the PCB for the screws, it is advisable to drill them about 4.5 - 5 mm so there is plenty of room for adjustment when lining up the LEDs with the acrylic.

IMPORTANT: The PCB should NOT be secured too firmly



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