How It Started

CozZie Glow began with a simple need: a small light inside the tent. Just a small LED with a
remote switch. Nothing more.

Then | started thinking about the harsh, narrow spectrum light of an LED. A potential migraine
trigger. Incandescent bulbs produce a much more natural light — but are hard to find in AC
varieties. DC, on the other hand, gives us 12V automotive bulbs. Perfect for a lamp. Low
voltage, safe, and easy to switch via solid state device.

| had SSRs in my parts bin — salvaged ten years earlier while decommissioning an old Train
Bearing Detector site, also known as a Wayside Inspection System. The relays were headed for
the garbage. Not at $50+ each. | salvaged 4 of them. High amperage, high voltage DC control. |
didn't know exactly how | would use them, but | knew they were too valuable to throw away.
Years later | learned they could PWM control a DC load via the Arduino Uno.

The Uno and the Pi were already in my inventory. So were some old IP cameras and a Chinese
NVR with a 1TB hard drive.

| didn't buy much. | built with what | had.

The Light Science — Incandescent vs LED

Light sources are not equal. The difference matters deeply for human biology.

An LED produces light by electroluminescence — electrons jumping across a semiconductor
gap. This produces light at a very specific, narrow wavelength. The "warm white" of an LED is
an illusion — a blue LED chip coated with yellow phosphor, tricking the eye into perceiving
warmth. The underlying spectrum is spiky and incomplete. Missing frequencies the human body
has expected from light sources for hundreds of thousands of years.

An incandescent bulb produces light the same way the sun does — by heat. A tungsten filament
heated until it glows. The result is a broad, continuous spectrum across all visible wavelengths,
plus infrared. The same physics as a campfire. The same physics as a sunset.

Incandescent bulbs are a fading technology — phased out globally in the name of efficiency.
That efficiency argument is valid. But something was lost in the transition that nobody has fully
accounted for. Your oven still needs one. LED traffic signals don't melt snow off the lens the way
incandescent signals did — cities discovered that the waste heat from an incandescent bulb
was doing a job nobody designed it to do. In extreme conditions, with no electronics to fail, the