PiLCD (node-red-node-pilcd) LCD only shows left 8x2 of 16x2 screen


#1

Hi All,

I've been creating a Node-Red Raspberry Pi temperature/humidity sensor set-up for my home, and I'd like to output the temperature and humidity values to my 16x2 LCD display.

The display is a 16x2 HD44780-type LCD display and I've wired it up as per the following diagram: http://i.imgur.com/89u9crv.png

I've installed the 'pilcd' node and I can successfully use a 'template' node to provide and display the temp and humidity.

However... the LCD display is only using the left 8x2 part of the display. Any string longer than 8 characters gets cut off.

Does anyone know if this is a problem with my wiring (which I've triple-checked...)? Or is this something that can be addressed in the code of the installed node?

https://flows.nodered.org/node/node-red-node-pilcd

Edit: fixed my broken hyperlinks (sorry, forum newbie)


#2

easiest way to check is probably to try writing to it NOT using Node-RED.

If it works it's an issue with the node or how you have configured it.


#3

Thanks for the advice, ukmoose.

I've tested it using python and I'm still missing the 8x2 characters on the right-hand side of the display.

import time
import RPi.GPIO as GPIO
from RPLCD.gpio import CharLCD
lcd = CharLCD(pin_rs=16, pin_rw=None, pin_e=18, pins_data=[32, 36, 38, 40],
              numbering_mode=GPIO.BOARD,cols=16,rows=2, dotsize=8,
              charmap='A02',
              auto_linebreaks=True)
lcd.write_string('Hello world!    Hello world!')
time.sleep(10)
lcd.clear()
GPIO.cleanup()

It's possible that the LCD display is defective, but I guess I'll check all my wiring again before I settle with that conclusion.


#4

I think i'm going to call this a defective LCD display. I've pulled every GPIO comms wire and the display won't function unless they are all connected in their current GPIO locations.

I'll order another LCD and make an update when I receive it.

Thanks again!