Difference between revisions of "RGB LED HAT"

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== How to use ==
 
== How to use ==
Perhaps the descriptions above is too verbose to understand but you can skip it and just use the corresponding libraries in your Raspberry Pi. In this case, you should copy the example program packages to your Pi and unzip them.
 
 
=== Libraries installation ===
 
=== Libraries installation ===
Copy the file rpi_ws281x-master.zip to your Pi, and run the following line to unzip it.
+
Install the libraries with the following commands:
unzip rpi_ws281x-master.zip
+
<pre>
 +
sudo apt-get install python3-pip -y
 +
sudo pip3 install rpi_ws281x -y
 +
</pre>
 
For the latest libraries, you can visit the website: https://github.com/jgarff/rpi_ws281x
 
For the latest libraries, you can visit the website: https://github.com/jgarff/rpi_ws281x
  
Install the depended-upon software
+
Download the examples and run them for a try
sudo apt-get install build-essential python-dev scons swig
+
<pre>
Compile the program
+
wget https://www.waveshare.net/w/upload/b/b2/RGB_LED_HAT.zip
cd rpi_ws281x-master
+
unzip RGB_LED_HAT.zip
sudo scons
+
sudo chmod 777 -R RGB_LED_HAT
: [[File:rgb-led-hat-user-manual-3.png]]
+
cd RGB_LED_HAT
Run the line below to perform testing. You can see the RGB LED flickering.
+
sudo python3 ws2812.py
sudo ./test
+
</pre>
Run the following line to install the python library.
 
cd python
 
sudo python setup.py install
 
Run the demo code for testing.
 
cd examples
 
sudo python lowlevel.py
 
 
* If the library is installed successfully, you can see the RGB LED flickering.
 
* If the library is installed successfully, you can see the RGB LED flickering.
 
<font color=red>
 
<font color=red>
* If the LED displays the wrong color, please add the lines below into the file /boot/config.txt, and restart the Pi to take them effect.
+
* If the LED displays the wrong color, please add the lines below into the file /boot/config.txt, and restart the Pi to take the effect.
  
 
* RGB LED adopts DMA control, which may occupy the video output DMA channel on the Raspberry Pi. Therefore, adding these lines may cause the earphone connector unusable.
 
* RGB LED adopts DMA control, which may occupy the video output DMA channel on the Raspberry Pi. Therefore, adding these lines may cause the earphone connector unusable.
Line 99: Line 95:
 
# <code>Adafruit_NeoPixel</code> creates an object strip, sets the number of the LEDs to 32, the pin to 18, and the frequency to 800000. The parameter <code>LED_BRIGHTNESS</code> is the brightness of the LED.
 
# <code>Adafruit_NeoPixel</code> creates an object strip, sets the number of the LEDs to 32, the pin to 18, and the frequency to 800000. The parameter <code>LED_BRIGHTNESS</code> is the brightness of the LED.
 
# <code>begin()</code> RGB LED initialization function.
 
# <code>begin()</code> RGB LED initialization function.
# <code>setPixelColor(pos, color)</code> This sets the pixel, of which pos is the LED position, and color is the RGB color
+
# <code>setPixelColor(pos, color)</code> This sets the pixel, of which pos are the LED position, and the color is the RGB color
# <code>color(r, g, b)</code> This converts the RGB value to a 24 bit color.
+
# <code>color(r, g, b)</code> This converts the RGB value to a 24-bit color.
 
# <code>show()</code> This transfers data, showing the set LED color.
 
# <code>show()</code> This transfers data, showing the set LED color.
 
# For more information about the functions, please see rpi_ws281x-master/python/neopixel.py
 
# For more information about the functions, please see rpi_ws281x-master/python/neopixel.py
Line 106: Line 102:
 
=== Web control with Bottle ===
 
=== Web control with Bottle ===
 
: [[File:rgb-led-hat-user-manual-5.jpg|thumb|200px|controlled by browser]]
 
: [[File:rgb-led-hat-user-manual-5.jpg|thumb|200px|controlled by browser]]
Bottle is a fast, simple and lightweight WSGI micro web-framework for Python. By Bottle, you can fast and easily implement Web control.
+
The bottle is a fast, simple, and lightweight WSGI micro web-framework for Python. By Bottle, you can fast and easily implement Web control.
  
 
Install the library
 
Install the library
sudoapt-get install python-bottle
+
<pre>
Perform web control RGB LED via Bottle
+
sudo apt-get install python3-bottle
cd ~/RGB LED HAT/web-RGB
+
cd RGB_LED_HAT/web/
sudo python main
+
sudo python3 main.py
 +
</pre>
 +
Perform web control RGB LED via Bottle. <br />
  
Then, enter the IP address of your Pi and the port number 8000 into the address bar of the browser. Clicking different position of the palette, the LEDs will display different colors. There are 3 display modes selectable, static, breath and flash.
+
Then, enter the IP address of your Pi and port number 8000 into the address bar of the browser. Clicking different positions of the palette, the LEDs will display different colors. There are 3 display modes selectable, static, breath, and flash.
* '''Note: This web-RGB program only supports the mobile phone browser. It is unavailable for PC browser. '''
+
* '''Note: This web-RGB program only supports the mobile phone browser. It is unavailable for PC browsers. '''
  
 
= Resources =
 
= Resources =

Revision as of 08:00, 4 May 2023

RGB LED HAT
True color RGB LED HAT for Raspberry Pi, colorful display
Rgb-led-hat-intro 1.jpg

True color RGB LED HAT for Raspberry Pi, colorful display
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Introduction

True color RGB LED HAT for Raspberry Pi, colorful display

More

Interfaces

  1. For Raspberry Pi, you only need to insert the product to the corresponding interface on the Pi;
  2. For other devices, you'd better to solder the pin headers to the pads of 5V, GND, DIN and DOUT for wiring.
Symbols Pin descriptions
5V 5V power supply
GND Ground
DIN Control signal input
DOUT Control signal output

Description

WS2812B is an intelligent LED controller of which the control circuit and the RGB chip are integrated in a package of 5050 components. It internally includes an intelligent digital port, a data latch and a signal reshaping amplification drive circuit. To ensure the color brightness consistent of the pixel light, it also contains a precision internal oscillator and a 12V voltage programmable constant current control part.

Its data transfer protocol uses a single NZR communication mode. After the pixel is power-on and reset, the DIN port receives the data from the controller. The first 24-bit data is collected by the first pixel and then sent to the internal data latch. The other data are reshaped by the internal signal reshaping amplification circuit and sent to the next cascade pixel through the DO port. After the transmission for all pixels, the signal may reduce to 24bit. The pixel adopts auto reshaping transmit technology, which allows the pixel cascade number is up to the speed of the signal transmission but not bound by the signal transmission restriction. For more information about auto reshaping transmit technology, please refer to the section data transfer protocol.

Sequence chart

Sequence chart
  • Data transfer time( TH+TL=1.25µs±600ns)
T0H 0 code, high voltage time 0.4µs ±150ns
T1H 1 code, high voltage time 0.8µs ±150ns
T0L 0 code, low voltage time 0.85µs ±150ns
T1L 1 code, low voltage time 0.45 µs ±150ns
RES The unit of frame, low voltage time Above 50µs

Data transmission method

Data transmission method

On the base of the data sequence, we can easily complete data transfer with the communication protocol.

Note: The data of D1 is send by MCU, and D2, D3, D4 are transmitted through pixel internal reshaping amplification.

  • Composition of 24bit data:
G7 G6 G5 G4 G3 G2 G1 G0 R7 R6 R5 R4 R3 R2 R1 R0 B7 B6 B5 B4 B3 B2 B1 B0
Note: The data is sent in the order of GRB and the high bit is sent at first.

How to use

Libraries installation

Install the libraries with the following commands:

sudo apt-get install python3-pip -y
sudo pip3 install rpi_ws281x -y

For the latest libraries, you can visit the website: https://github.com/jgarff/rpi_ws281x

Download the examples and run them for a try

wget https://www.waveshare.net/w/upload/b/b2/RGB_LED_HAT.zip
unzip RGB_LED_HAT.zip
sudo chmod 777 -R RGB_LED_HAT
cd RGB_LED_HAT
sudo python3 ws2812.py
  • If the library is installed successfully, you can see the RGB LED flickering.

  • If the LED displays the wrong color, please add the lines below into the file /boot/config.txt, and restart the Pi to take the effect.
  • RGB LED adopts DMA control, which may occupy the video output DMA channel on the Raspberry Pi. Therefore, adding these lines may cause the earphone connector unusable.

hdmi_force_hotplug=1
hdmi_force_edid_audio=1

Demo descriptions

Running the demo ws2812.py, you can see the RGB LED display the gradient color.

cd RGB_LED_HAT
sudo python ws2812.py
Rgb-led-hat-user-manual-4.png
  1. from neopixel import * import the library rpi-ws281x
  2. Adafruit_NeoPixel creates an object strip, sets the number of the LEDs to 32, the pin to 18, and the frequency to 800000. The parameter LED_BRIGHTNESS is the brightness of the LED.
  3. begin() RGB LED initialization function.
  4. setPixelColor(pos, color) This sets the pixel, of which pos are the LED position, and the color is the RGB color
  5. color(r, g, b) This converts the RGB value to a 24-bit color.
  6. show() This transfers data, showing the set LED color.
  7. For more information about the functions, please see rpi_ws281x-master/python/neopixel.py

Web control with Bottle

controlled by browser

The bottle is a fast, simple, and lightweight WSGI micro web-framework for Python. By Bottle, you can fast and easily implement Web control.

Install the library

sudo apt-get install python3-bottle
cd RGB_LED_HAT/web/
sudo python3 main.py

Perform web control RGB LED via Bottle.

Then, enter the IP address of your Pi and port number 8000 into the address bar of the browser. Clicking different positions of the palette, the LEDs will display different colors. There are 3 display modes selectable, static, breath, and flash.

  • Note: This web-RGB program only supports the mobile phone browser. It is unavailable for PC browsers.

Resources

Documentation

Software

Others

Support

If you require technical support, please go to the Support page and open a ticket.,