Yet another display 16x2 not working with arduino

Other Hardware Displays
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I found hundreds of questions about display not working with arduino. However, no matter how trivial this looks like I am having the same problem I cannot understand by reading the other posts.

I have an Arduino micro connected to a display from the adafruit kit (RGB LCD SHIELD KIT W/ 16X2 CHARACTER DISPLAY https://www.adafruit.com/product/714) I haven't been able to understand whether positive or negative, but I think from the picture is RGB positive.

I have connected everything as shown in the diagram in this page: https://www.arduino.cc/en/Tutorial/HelloWorld Obviously changing the pins as I have RS at 8 E at 7 and d4 = 12, d5 = 11, d6 = 10, d7 = 9; The potentiometer changes the contrast, if I saturate it I can see the black boxes. In the code put this as

const int rs = 8, en = 7, d4 = 12, d5 = 11, d6 = 10, d7 = 9;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

and the rest as the example in the link,

This is my mess (please ignore the other arduino and the thermocopler which is not connected, the other orange wire goes to GND of the Arduino).

2285×1714 556 KB

I checked with the multimeter whether the soldering is good and it carries the signal at the end of the wires.

any ideas?

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Was it connected when you had your power supply issues?

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I haven't been able to understand whether positive or negative, but I think from the picture is RGB positive.

It doesn't matter which of these devices you have, both descriptions include this phrase:
"We had these custom made to our specification so that you can use them in existing LCD projects and they'll still work - just that only the red LED will be used. The extra two pins (17 and 18) are for the green and blue LEDs."

In other words if you use the first 16 pins the device will work like any other 16x2 display except that the color will be red.

This means that (at the least) your four data pins are connected incorrectly at the LCD end. They should be connected to LCD pins 11, 12, 13, and 14 not to the pins you are using.

Don

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thanks, I skipped that part :confused:
You are probably right, I will try soon

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You were right.Thank!
It is working now. it is only red but it is working

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Move the wire from pin 16 to 17 or 18 to get the other two colors.

Untested:

  • Control pins 16, 17, and 18 via Arduino digital outputs to get some color combinations.
  • Control the pins using pwm for more combinations.

Don