node-red-contrib-st7735s

Node-Red node to talk to ST7735S TFT displays, connected by Raspberry Pi's SPI. The node is using JSPyBridge to provide the JS bindings for the Python ST7735 using Standard Error as the IPC. Additionally, all the functionalities provided is using the PIL Image and ImageDraw module. Requires Node.JS >= 16 and Python to be installed.

Usage

Enable SPI

Enable the Raspberry Pi SPI interface via GUI or raspi-config

Install the Python ST7735 from Pimoroni:

Python2

sudo apt update
sudo apt install python-rpi.gpio python-spidev python-pip python-pil python-numpy

sudo pip install st7735

Python3

sudo apt update
sudo apt install python3-rpi.gpio python3-spidev python3-pip python3-pil python3-numpy

sudo python3 -m pip install st7735

Run the python examples to make sure its working. This node fully rely on this installation to be working.

Install node-red-contrib-st7735s

cd ~/.node-red
npm install node-red-contrib-st7735s

or install it via NodeRed pallete manager.

Config:

The default value should be working for 0.96' ST7735S IPS LCD display. However, take note on the Width and Height values. The ST7735s has a Frame RAM of ST7735_COLS = 132 and ST7735_ROWS = 162. The number of columns is less than the columns of the display (160). Thus the width is set to 80 and the height to 160 then rotated 90 degree.

The default value of Offset Left and Offset Top is given by Python ST7735 library however it produces some undesirable artifacts on my testing unit. Setting it to:

Offset Left = 24
Offset Top = 0

seems to eliminate it.

Features

• Tested with Raspberry Pi 4B.
• In the examples directory there is a flow (example.json) that you can use for testing.
• Read the node docs for details operation.
• Be mindful of PlayGif and TextScroll node. These nodes needs to be stopped with StopGif and TextStop before drawing another stuff on the LCD.

If you are seeing this error when stopping the NodeRED:

Traceback (most recent call last):
  File "/home/pi/Pimoroni/node-red-contrib-st7735s/node_modules/pythonia/src/pythonia/interface.py", line 53, in <module>
    com_io()
  File "/home/pi/Pimoroni/node-red-contrib-st7735s/node_modules/pythonia/src/pythonia/interface.py", line 42, in com_io
    data = apiin.readline()
  File "/usr/lib/python3.9/socket.py", line 704, in readinto
    return self._sock.recv_into(b)
KeyboardInterrupt

It is ok. It just the JSPyBridge things.

Please Contact Us

If you have any problem when using our package, please contact us..