9. Multi-color LED (WS2812)¶
Multi-color LED (WS2812) is an integrated LED chip which can create different RGB color. Using programming, user can pick any one of color in 16 million color and showing it.
9.2. The principle¶
The WS2812 have a small chip inside the module, which handle the incoming data and communicate with the next WS2812B in the serial. WS2812B operation under digital, user need to follow the special logic representation to transmits the data.
WS2812 allow connect to other WS2812B and share the signal line, but benefit from the data transmission policy, it can use the single line to control all the light individually.
For each WS2812, there are three 8bit color LED (Green, Red, Blue) inside, so each WS2812 required total 24bit of data in once action.
After the 24 bits data read by WS2812, the remaining data bit will pass to next WS2812(if need), so the next WS2812 is possible to read another set of data to produce different color.
When all the data bit is sent, another 50us reset code is required to let chip understand the transmission is end and control the led to emit the light.
Supply Voltage: 3.3V to 5V
Range of Color: (0,0,0) to (255,255,255)
9.4. Pinout Diagram¶
9.5. Outlook and Dimension¶
Size: 25mm X 25mm
9.6. Quick to Start/Sample¶
Connect the sensor to development board (direct plugin or using wire)
Open Makecode, using the https://github.com/smarthon/pxt-smartcity PXT
Use to PXT library to control the LED showing different colors
The WS2812 following the program to change the color