It’s hard to think of a more obvious use for electricity than producing artificial light. In the early days of practical electrical engineering, electricity became almost synonymous with artificial light — the average person didn’t have much else to use electricity for in their homes. It’s incredibly easy to make your own electric lights, as there are types of light bulbs that can be plugged directly into both direct current (DC) and alternating current (AC) sources. But what if you want something a little fancier than a simple light bulb? That’s what Andrew Bejcek wanted when he built a colorful nightlight called Electric Prism.
When plugged into a power source, the Electric Prism will glow pleasantly and cycle through a colorful rainbow of gentle light. The brightness of that light is dependent on the ambient light in the room and can also be set explicitly with a capacitive touch slider. Those features alone would make the Electric Prism an ideal nightlight for most people, since the brightness can be set to the optimal level to sooth you into a deep slumber. But the light is controlled entirely with a microcontroller, which means it can be reprogrammed to act however the user desires. Bejcek believes that could make it ideal for helping kids learn STEM concepts.
The Electric Prism is based on a small PCB that Bejcek designed himself in KiCAD. That PCB contains just a handful of components: a Microchip ATmega328P, eight WS2812B RGB LEDs, a USB-A connector, a CH330N USB-to-Serial chip, and a few resistors and capacitors. Power is provided through the USB connector, so it can be plugged into a cell phone charger in a wall outlet. It can also be reprogrammed via the CH330N chip when it is plugged into a computer, using the Arduino IDE. Finally, a 3D-printed cover helps to diffuse the light from the LEDs.
Bejcek has uploaded the design and code to his blog.