Is my 20 x 4 LCD Broken?

Hi everyone,

I recently hooked up a 20 x 4 LCD to my Arduino Uno. I have it set up for an aquarium and the LCD displayed the time, light settings, and water temperature.

I followed this tutorial (Overview | Character LCDs | Adafruit Learning System) to hook everything up and it was working fine for a few days.

Here is what it looked like.

The LCD is embedded in a cabinet door and the other day I opened the door to get inside the cabinet. When I looked at the LCD again it looked like this.

I have since fiddled with the contrast pot, and checked with my multimeter to confirm that all the wire connections are good and they are.

The display seems to be flickering at a rate that is consistent with when the clock and temperature information should be updated. So I think the Arduino is sending some signals to the display. And the light controller and temperature sensor are working properly based on observing the serial monitor.

I have also uploaded sample test code for the display itself and that doesn't change anything.

I guess my question is, is the LCD itself busted? Does anyone have other ideas as to what I could do?

The LCD is a niceeshop(TM) 2004 LCD Module for Arduino 20 x 4. It was only $6, so maybe I just got what I paid for? haha

Hi and welcome.

Read some topics concerning these 1602 and 2004 displays.
There's loads of tips over here.
1602 and 2004 use the same technology, and so the problems people have are similar.
The picture shows a display that isn't initialised.
Sending data to a display that isn't initialised correctly doesn't make much sense and will get you this result.

There's some possible reasons for this to happen.
First and easiest, is to check your code.
If it worked before, and suddenly stopped, and/or if you have uploaded another code that has worked in the same setup, it will be unlikely that this is going on here.
Next is a hardware failure.
Suspect your own work first.
Check, double check and cross check your work.
Then ask someone else to have a fresh look at it, people tend to not see their own mistakes.
Consider re-wiring the display.

Sure, a defect on the module itself is possible.
But try to rule out any other possibilities before you blame that module.
If you'd happen to have another display available, try that one.

I have since fiddled with the contrast pot, and checked with my multimeter to confirm that all the wire connections are good and they are.

This has nothing to do with your contrast pot and everything to do with a bad connection.

Don