It isn't I want to try for the title of "Most active posts". I am trying to keep things segmented.
I am faced with this scenario:
I have a PiFaceCAD hat for the RasPi. It works.
It came with some python scripts and they work.
(Well, that's a bit debatable. However.)
There is a problem though, and thus me posting:
Say I use their script to write to the display:
I send "Hello there". (Quotes included)
I see Hello there
on the screen. No big. The "
absorbs the space and make the two words one parameter.
But if I run the script again: The display blinks (LED/backlight goes off then on); the display is wiped and Hello there
is again displayed. But in the same position as before.
If I open a CLI (terminal) and type python
and basically set things up with import sys
and import pifacecad
then enter the command to write "Hello there" I get Hello there
on the screen.
I enter the command again and this time I see a second Hello there
on the screen appended to the first.
The display doesn't blink. It isn't cleared!
(I think it is now customary to say.....) Woo Hoo!
So....... Thinking about it.
And with help from other research.
When the python
code is invoked (the session - if you will) it initialises things. And part of that is clearing the display.
However, when I am still in python
via the CLI, that is only done ONCE, and I don't get the initialisation done every time the script is run.
This is a concern, as I want to write a flow in Node-Red which writes data to the display at co-ordinates I give in the message.
The last thing I want is every time a messages is sent, the rest of the display is wiped. (And the backlight is turned off then back on.)
So, are my theories correct in what is happening? (Kind of a bit late. I have ordered the hardware)
But if this theory is true: I could hack the python stuff and negate the initialisation stuff and set it as a new parameter I can send to the display.
Yes, it is murky waters into which I am sailing. But I am hoping this is a learning curve which I can over come.
I'm asking here because it is how Node-Red interacts with python
which is of interest.
Another way is that I could set variables in/via Node-Red and have a python script that merely echoes those onto the display.
But that is whole other way of doing it.
I'd prefer the prior way.