16x2 LCD doesn't want to show text [SOLVED]

Other Hardware Displays
1

Hello,

I bought this LCD screen on Ebay: LCD 16x2 with backlight
When I want to try it, it doesn't want to work, only the backlight turns on. I made a photo so you can see the wires.

Someone who see my mistake or is it just broken?

regards,
minitreintje

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2

You cannot leave pin 3 (V0) open.

You should be using a 10K potentiometer with it's ends connected to pins 1 and 2. The center of the potentiometer goes to pin 3.

If you do not have a potentiometer you could try connecting pin3 to GND (pin 1) although that might not give optimum results.

Don

3

Thanks for your reply.
Is a resistor also good?

And sometimes they connect RW to ground and sometimes they connect it to an Arduino pin. Is there a difference?

regards,
minitreintje

4

SOLVED! I added a 10k resistor on 0V and it works, not perfectly good contrast but I can read the text :slight_smile:

minitreintje

5

minitreintje:
SOLVED! I added a 10k resistor on 0V and it works, not perfectly good contrast but I can read the text :slight_smile:

minitreintje

That is really no different than just connecting pin 3 to GND. It is acting like a pull-down resistor.

If you want to use resistors then the 10K goes from pin 3 to +5 and a 1K goes from pin 3 to GND. This will create a voltage divider that puts a bit less than 0.5 v on pin 3, a value that frequently gives good results.

Don

6

And sometimes they connect RW to ground and sometimes they connect it to an Arduino pin. Is there a difference?

With all versions of the LiquidCrystal library so far there is no difference. All the library does is drive the R/W pin low and keep it there.

Don

7

Thanks for your reply :slight_smile:

minitreintje