Display difficulty with pifacecad hat

General
1

I have one of these:

PiFace CAD hat.

It is a 2 x 16 LCD display.

There is a node for it and I made it better in that you can specify where on the display the message is set.

This is the basis of a new project I am about to start which may seem over the top, but hey..... I am wanting to give it a go.

I think I have found a 3.3v display and a compatible SPI bus driver for it. (Less pins used on the RasPi.)

The thing is I can't send a : to be displayed.

I am wanting to display a : and a / and a few other special characters.

I can understand that some characters are special and need to be handled differently.

Anyway, if I send a message hello world all I see on the display is hello. The world part is negated - probably because of the (space).

No big. I send it "hello world" and I see the message hello world. Great.

But if I then send it "hellow:world" all I see is hello again.

This is using the code supplied with the node.

#
import pifacecad
import sys

try:

     x = sys.argv[1].split(",")
     y = x[1].split(":")
except:
    raise TypeError("The entered text is not correct")

cad = pifacecad.PiFaceCAD()
cad.lcd.backlight_on()
cad.lcd.cursor_off()
cad.lcd.set_cursor (int(x[0])-1, int(y[0])-1)
if (y[1]):
    cad.lcd.write(y[1])

    cad.lcd.blink_off() 
#    cad.lcd.write(unicode(text))
else:
    cad.lcd.clear()

This code - however - displays the : in the message.

#!/usr/bin/env python3
 
import sys
import pifacecad
 
#print('Arguments:', len(sys.argv))
#print('List:', str(sys.argv))
 
#if sys.argv < 2:
#    print('Too few arguments, please specify a filename')
 
filename = sys.argv[1]
print('The paramater you entered is called')
print( filename)

cad = pifacecad.PiFaceCAD()
cad.lcd.backlight_on()
cad.lcd.clear()
cad.lcd.write(filename)

I shall sit down and try to work out what is going on, but as far as I can see, they are both using this piface thing at the start to display the message.

And they are both using:
cad.lcd.write( to write to the screen/display.

So I at a loss to see what is going on and why.

If someone is feeling kind. A bit of help would be appreciated.

2

You may be better asking on their github page as you are into the depths of their code not Node-RED

3

Yeah. I was just wanting to ask among people who know me and can maybe answer in ways I understand quicker.

No problem.

Oh, and the github where I got the node is very poorly supported.
It was written by the person for a purpose and they are sharing it but the code is problematic and I mentioned a couple of problems to which I got a dismissive reply.

I don't think help will be too easy to get.

4

Line 4 of the code splits the input on : and uses the first part to set the line to display on. So yes that would remove all :

5

So I would have to do something like:

cad.lcd.write(y[1])
cad.lcd.write(y[2])
cad.lcd.write(y[3])

To see all the numbers?

Sorry, I'll go away and look at the code again.

6

I went in and changed the line to:
y = x[1].split(";")

and changed the command from:
1,1:"Hello world"
to
1,1;"Hello world"
Didn't work.

So I am missing something else.

Don't worry. I'll see if I can work it out.

7

I thought split( splits the string at that character. Not so much removing them.

8

It does split on the character, and returns an array containing only the text between those characters (not the character itself).

9

Ok. Thanks.

10

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