Average rainfall 2001-2016, global tropics

Map: Average rainfall 2001-2016, global tropics

Module Project Nano

component: SMD 5050 Programmable RGB LED

Thomas Gumbricht bio photo By Thomas Gumbricht

Introduction

These SMD 5050 components are individually addressable RGB LEDs - this means with just 3 wires, you can make each LED turn any one of 16 million colours. There a many different versions: WS2811/WS2812/WS2812B/APA104/APA106/SK6812, but all work the same way electrically. Espruino have a short introduction to programmable LEDs. The Youtube LED Strips, what’s the difference is more in depth and explains some of the differences between the listed components. It is a good point to start when selecting what kind to chose for your project. At Alibaba you can get the components at 0,02 US$ - 0,10 US$ a piece.

Single ws2812 LED component.

Dimming

LED light (and ELD strips) are not dimmable in the conventional sense. Attempting to vary the brightness of the LEDs by changing the external voltage is impractical. However, they can be dimmed using pulse-width modulation (PWM) dimmers. These rapidly switch the LEDs on and off, typically 500 times per second, by changing the voltage from zero to the expected value as a square wave. The relative width of the on and off portions of the square wave can be varied so that the LEDs are on or off for relatively more or less time to change brightness. Addressable LEDs (as in LED strips) do this dimming internally given a data signal with colour intensity information, while non-addressable LEDs require an external PWM controller to be dimmed.

Whether the PWM dimming is useful for adjusting the illumination for a spectrometer remains to be determined.

Module Project Nano