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In this article, the editor introduces in detail "how to achieve colorful racing lanterns in Python". The content is detailed, the steps are clear, and the details are handled properly. I hope that this article "how to achieve colorful racing lanterns in Python" can help you solve your doubts.

I. purpose of the experiment

Understand how ws2812b works

Learn the driving method of ws2812b

2. Experimental equipment

TPYBoard v102 1

1 ws2812b RGB-Ring-8

1 micro USB cable

Some DuPont lines

III. Introduction of WS2812B

WS2812B is an intelligent external control LED light source which integrates control circuit and light emitting circuit. Its appearance is the same as a 5050LED lamp bead, and each element is a pixel. The pixel contains intelligent digital interface data latch signal shaping and amplification drive circuit, high-precision internal oscillator and programmable constant current control part, which effectively ensures that the color of the pixel light is highly consistent.

The data protocol adopts the communication mode of single-line return-to-zero code. after the pixel is powered on and reset, the DIN terminal accepts the data transmitted from the controller. The first 24bit data is extracted by the first pixel and sent to the data latch inside the pixel. The remaining data is reshaped and magnified through the internal shaping processing circuit and then forwarded and output to the next cascaded pixel through the DO port. For each transmission through a pixel, the signal is reduced by 24bit. The pixel adopts automatic shaping and forwarding technology, so that the number of cascades of the pixel is not limited by the signal transmission, and only the signal transmission speed is limited.

Physical drawing

The picture above is of eight lamp beads.

The pin description of the WS2812B:

Hardware connection

The wiring diagram of TPYBoard v102 and WS2812B is as follows:

The source code of the program is as follows:

Import pybimport math from ws2812 import WS2812 ring = WS2812 (spi_bus=1, led_count=8, intensity=0.1) def data_generator (led_count): data = [(0,0) 0) for i in range (led_count)] step = 0 while True: red = int ((1 + math.sin (step * 0.1324)) * 127green = int ((1 + math.sin (step * 0.1654)) * 127blue = int ((1 + math.sin (step * 0.1654)) * 127data [step% led_count] = (red, green) Blue) yield data step + = 1 for data in data_generator (ring.led_count): ring.show (data) pyb.delay

You also need to import a ws2812.py file inside. The contents are as follows:

Import gcimport pyb class WS2812: "Driver for WS2812 RGB LEDs. May be used for controlling single LED or chain of LEDs. Example of use: chain = WS2812 (spi_bus=1, led_count=4) data = [(255,0,0), # red (0,255,0), # green (0,0,255), # blue (85,85,85) # white] chain.show (data) Version: 1.0 "" buf_bytes = (0x11, 0x13, 0x31, 0x33) def _ _ init__ (self, spi_bus=1, led_count=1 Intensity=1): "Params: * spi_bus = SPI bus ID (1 or 2) * led_count = count of LEDs * intensity= light intensity (float up to 1)"self.led_count = led_count self.intensity = intensity # prepare SPI data buffer (4 bytes for each color) self.buf_length = self.led _ count * 3 * 4 self.buf = bytearray (self.buf_length) # SPI init self.spi = pyb.SPI (spi_bus Pyb.SPI.MASTER, baudrate=3200000, polarity=0, phase=1) # turn LEDs off self.show ([]) def show (self, data): "" Show RGB data on LEDs. Expected data = [(R, G, B),...] Where R, G and B are intensities of colors in range from 0 to 255. One RGB tuple for each LED. Count of tuples may be less than count of connected LEDs. " Self.fill_buf (data) self.send_buf () def send_buf (self): "Send buffer over SPI." Self.spi.send (self.buf) gc.collect () def update_buf (self, data, start=0): "Fill a part of the buffer with RGB data. Order of colors in buffer is changed from RGB to GRB because WS2812 LED has GRB order of colors. Each color is represented by 4 bytes in buffer (1 byte for each 2 bits). Returns the index of the first unfilled LED Note: If you find this function ugly, it's because speed optimisations beated purity of code. " Buf = self.buf buf_bytes = self.buf_bytes intensity = self.intensity mask = 0x03 index = start * 12 for red, green Blue in data: red = int (red * intensity) green = int (green * intensity) blue = int (blue * intensity) buf [index] = buf_ bytes [green > > 6 & mask] buf [index+1] = buf_ bytes [index+2] = buf_ bytes [index+2] = buf_ bytes [green > > 2 & mask] buf [index+3] = buf_ bytes [green & mask] buf [index+4] = buf_ bytes [red > > 6 & mask] buf [index+5] = buf_ bytes [red > > 4 & mask] buf [index+6] = buf_ bytes [red > > 2 & mask] buf [index+7] = buf_ bytes [red & mask] buf [index+8] = buf_ bytes [blue > 6 & mask] buf [index+9] = buf_ bytes [blue > > 4 & mask] buf [index+10] = buf_ bytes [blue > > 2 & mask] buf [index+11] = buf_ bytes [blue & mask] index+ = 12 return index / / 12 def fill_buf (self Data): "" Fill buffer with RGB data. All LEDs after the data are turned off. " End = self.update_buf (data) # turn off the rest of the LEDs buf = self.buf off = self.buf_bytes [0] for index in range (end * 12, self.buf_length): buf [index] = off index + = 1 here, this article "how to achieve colorful racing lanterns in Python" has been introduced. If you want to master the knowledge of this article, you still need to practice and use it. If you want to know more about the articles, you are welcome to follow the industry information channel.

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