LCD RC1602BB problems


I wired this lcd up and ran the hello world, but its not working. ive triple checked my wiring and cant find anything wrong!
I also changed the code in hello world to match the pins on the arduino (2,3,4,5,6,7)!

i hope these photos help!

all black leads are ground and red are 5v, rainbow is RS, E and data pins.

i really dont understand whats going on?

Pin 3 on your LCD has a red wire. You said that the red wires are connected to 5v but I think pin 3 should be used as a contrast adjustment.

For the 16 x2 LCD currently on my breadboard, pin 3 has to be tied to ground. Even connecting it to ground through a 10 K ohm resistor doesn't work. (It's okay with a 300 ohm resistor.) I'm not sure why it acts this way - I think I've got it properly grounded using pins 1 and 16 but it does. I did spend a whole $2 on this LCD so maybe it's faulty. Experience has shown that it's more likely to be me.

Also, are you sure that you've got D5 and D6 correct? They look switched to me.

Sorry bout than, pin 3 is connected to the middle pin of a 1K POT, while its other 2 pins are hooked up to ground and 5v.

the pins go brown, red, orange , green, yellow, blue . and these are RS, E, D5,6,7,8.

im almost 120% this is wired correctly, its not my first LCD, i have got others to work.

Could the LCD be busted? or tbhe arduino? both are brand new!

its just super wierd and im stumped!

Please HELP!!!

I tried it again this morning, hooked it up and ran the hello world, this is what i get:

im stumped!

Just a bit of an update, the contrast knob works fine (1k pot), but still all it displays is jiberish...

im thinking smthing is wrong with this lcd, i have an identical one and will try that one later today...

In my first response, I suggested you look at D5/D6. You responded that you'd rechecked the wiring but you didn't specifically address these two.

In your original post:

the pins go brown, red, orange , green, yellow, blue . and these are RS, E, D5,6,7,8.

arduino (2,3,4,5,6,7)
I think that the LCD nomenclature is actually D4, D5, D6 and D7. Using these pin assignments and your first picture, the yellow wire is connected to pin 5 and is LCD D5.

In the second picture, the yellow wire is connected to LCD D6 instead of D5.

Could the LCD be busted? or tbhe arduino? both are brand new!
If you can execute other sketches on the Arduino (e.g., "Blink"), I think it's unlikely that the Arduino has failed. I have ordered LCDs from eBay several times and some of the devices don't exactly agree with the spec. I think this is true with my current breadboarded LCD. All the devices I've purchased have worked, sometimes they've worked eventually.

Your plan to use an alternate LCD should help isolate the problem.

OMG, i think you are right and im a colorblind imbecil :slight_smile:

the green and yellow seem to be switched, ill try it when i get home!


Jups, you were right!

the lesson here is: get plenty of sleep before you hook up your lcd - that will avoid you asking silly questions on the forum :slight_smile:

cheers mate, and thanks again!

I'm glad it's working.

If people really learned from their mistakes, I'd be a genius.