Everything works fine for a while.
After 1 minute, the dimmer of the lcd changes (too high or too low)
So I adjust the potentiometer and it works fine again.
But after few seconds, the display shows strange characters (unreadable)
So I unplug the USB for a few minutes and set it again.
Hurray, it works again ... for a few seconds >:( (max 30 sec)
(and I can repat the process again & again)
Can it be a problem when I soldered the connectors to the display ?
Today, I bought a new LCD: gmd1602a lcd xiamen ocular.
I changed the voltage from 5V to 3.3 V.
Same result, after 10 seconds, the second row disappears and replaced progressively by stange characters.
I see that you have a yellow jumper connecting the two halves of one of your breadboard power rails but I don't see a corresponding jumper on the other rail. If your power rails are indeed separated by a gap this could be your problem.
I have seen worse soldering but there still may be some problems with yours. You certainly don't need any more solder but it wouldn't be a bad idea to reheat some of your joints and get the fillet to completely surround the pins as they come through the pc board.
floresta:
I see that you have a yellow jumper connecting the two halves of one of your breadboard power rails but I don't see a corresponding jumper on the other rail. If your power rails are indeed separated by a gap this could be your problem.
I have seen worse soldering but there still may be some problems with yours. You certainly don't need any more solder but it wouldn't be a bad idea to reheat some of your joints and get the fillet to completely surround the pins as they come through the pc board.
Don
Just curious - how does fritz (ing ) knows that the peg board HAS TWO power rails?
The yellow jumper connect ONLY ground rails together !
The LCD has no power to the controllerr , only the contrast has power.
@Vaclav
I cannot figure out why you have responded to my post but I will respond to yours!
I don't know anything about fritzing. I didn't look at his fritzing diagram because that merely indicates what he is trying to do, not necessarily what he actually did do.
We do not know if his breadboard does or does not have a gap in the power rails. Some do and some don't. Therefore we cannot state for sure whether he has an extra jumper or a missing jumper.
Your last statement is only correct if there are indeed gaps present and I am inclined to believe that this is actually the case. We won't know for sure until Philippe returns.
Disconnect your back light. You don't know how much resistance (or at all) the back light LED is in series with. It may be drawing too much current. Also disconnect your sonic ranger, see if your display lasts for longer. Ranging with ultrasound takes a lot of instantaneous power. If the power wire is anywhere near a display data wire, it interferes with the display.
Thank you for your answers.
As proposed by Floresta "it wouldn't be a bad idea to reheat some of your joints and get the fillet to completely surround the pins as they come through the pc board."
And now every thing works perfectly (the first LCD as well as the second one).
Concerning the yellow missing jumper:
In version 2: I used the left part of the breadboard with 3.3V and the right side with 5V because I saw on the LCD sheet that voltage is 3.3V for the second LCD. It was a bad idea so I removed the 3.3V and added the jumper to provide 5V.
