This project did not to work so well as an integrating sphere, but did perform effectively at illuminating food and drinks while retaining coolness.
The finished project. Not much throw.
Opening up the outer skin for the first LED. A single LED worked great, until I filled the chest with beer bottles and found they stopped the light like a brick wall. So I put one on each side down low to make the ice glow, and a third up high in the center as a catch-all.
Wires were run by pushing a coat hanger under the outer skin, through the foam insulation. Wires were also tucked under the lip to get to the other two sides for the other two LEDs.
Wires run. Battery pack will be under the handle for protection.
Surface prepped for gluing the battery pack by sanding with 150 grit and scoring with a blade to promote adhesion. Ice chest exteriors are made with high density polyethylene (HDPE) which no glue will adhere to well (I learned more than I wanted to know about plastics on this project). The least bad adhesive I found was JB Weld Plastic Bonder two part urethane. Screws were also used at the corners.
The 3xAAA battery pack fit perfectly below the handle, so it should be protected from getting smashed. I could not find any waterproof AAA packs, so rather than try to seal it, I drilled a couple of drain holes so it can dry easily. For this low power project, current limiting resistors were used. Two 12 ohm resistors in parallel allow about 240 mA with alkaline batteries. A proper BLF project would have an 18650 buried under the skin with USB charge port, but this ice chest was built as a gift for a friend who is technically challenged and disposable batteries made the most sense. This friend is also nearly blind (retinitis pigmentosa ) but likes to go camping, thus the need for an illuminated ice chest.
Magnetic reed switch (normally closed) being placed under the lip to turn the light off when the lid is closed. The angle and height of the switch have to be nearly perfect to get the magnet to activate it, so power has to be applied and the function tested continuously as the switch is being pressed and glued into place. It took several hours of trial and error to get it right.
Broken reed switch. I installed four switches before getting it to work. DO NOT buy the reed switches sold on Amazon. They are garbage. They break with the slightest pressure, and half of them were high impedance right out of the box. Get quality switches from Mouser or DigiKey.
Recess cut into lid for magnet.
Magnet glued into place. Rare earth magnet was scavenged from an old DVD drive.
Insulation dug out and 6mm hole drilled through the inner liner.
Window cut from a PVC soap bottle.
Window glued into place (with 2 part urethane), I modded two other ice chests for practice before tearing into this one and discovered that Coleman uses HDPE for the inner liner, but Igloo uses polypropylene (PP). For the Igloo, I was able to melt clear PP from an extra baby bottle cap into the liner with a micro torch to form a seamless window instead of gluing. HDPE unfortunately does not melt and flow and glue worked best.
This picture shows an XT-E, but I ended up using some leftover XQ-E HIs. Pretty much any LED would work for this, and star boards are unnecessary, but I had no other use for these parts.
There is an XQ-E HI buried under that giant glob of silicone.
Star board pressed into place onto the window.
Testing.
Replace the insulation with spray foam.
HDPE “welded” back together with a soldering iron. The foam expanded and started escaping before I could seal the bottom so I had to wait for it to cure and scrape off the excess before I could finish melting the plastic back together. I did a much better job on the other two sides but didn’t photograph them…
In use at Anza-Borrego!
) mod, and nicely documented. Thanks for posting.