Display-o-tron 3000 ello world


#1

Hi, just received my first pi, the 3, with a lovely display-o-tron 3000, set the whole lot up and ran the sample “Hello World” code which for some reason outputs “ello World”. Any clues?


#2

This is a fabulously obscure problem which is related to the lack of a reset signal for the LCD on Display-o-Tron 3000. If you power down and reboot your Pi/Dot3k combo it should work properly. The classic: “Have you tried turning it off and on again.”

I’ve never managed to replicate it consistently enough to figure out how to make it go away, but it’s a weird state the Display-o-Tron LCD gets into where everything is shifted off one character to the left.


#3

I tried rebooting several times and even put it on the Pi 2 I received with the 3. Same deal. And to make things weirder, while the hello world example outputs “ello World”, the bargraph example outputs “llo World”. Consistently.


#4

Hi guys,
Have exactly the same problem, pretty reliable. A fix would be really appreciated. Possible Pi3 issue?
Thanks, Dom


#5

I don’t think I’ve got a Dot3K or DotHAT with me, but I believe @RogueM might have found a solution so we’ll probably have a fix out soon!


#6

yes, I’m investigating the matter though as @gadgetoid said it’s not clear what exactly is the culprit.

for the time being, just enforce a reset of the cursor position straight after clearing the display, like so:

lcd.clear()
lcd.set_cursor_position(0,0)

… at least it seems to help and provide reliable results here.