New to LCDs

I just got Arduino (Uno) and I want to use the LCD that came w/ it (I got the Ultimate Microcontroller Pack, by Makershed). How should I connect it to the Arduino? Should I solder wires to the connection points? Should I connect it to a breadboard (one for itself) and wire it from that? Thx

go with the breadboard option!

Arduino Tutorial - connecting a parallel LCD and follow this tutorial, it covers a fair bit of info, and does everything step by step (on a breadboard)

enjoy!

Thanks! :slight_smile:

Should I solder wires to the connection points?

That is what I did when I got my first LCD.

Later if you want to put your LCD elsewhere, you can use some male/female jumpers and the mounting holes on the LCD sold at pololu.com

I'm having a problem with my LCD. I'm following this tutorial - Arduino Tutorial - connecting a parallel LCD - I have the same LCD, but I can't get past the first step. My arduino's (UNO) LCD doesn't turn on or show anything on it. No squares or backlight. Any help?

My board ATM -

Looks to me that your breadboard probably has a break in the +5v and ground lines, right where there is a break in the blue line next to the ground line. However, this may have saved you from burning out the backlight, since most LCD displays need a resistor in series with the backlight. If you don't know the backlight power requirement for that particular LCD, try a 150 ohm series resistor.

dc42:
Looks to me that your breadboard probably has a break in the +5v and ground lines, right where there is a break in the blue line next to the ground line. However, this may have saved you from burning out the backlight, since most LCD displays need a resistor in series with the backlight. If you don't know the backlight power requirement for that particular LCD, try a 150 ohm series resistor.

Thanks, I resoldered the connections, plugged it in, and tried again. It turned on. I'm going to put that resistor in though, considering you probably know much more about this than me!

I added the resistor, and I can't even see if the backlight is on! Help?

Bump

I suspect that the resistor you are using is much higher than 150 ohms, or that you have connected it incorrectly. Can you post a photo? Also, if you can post a link to the lcd datasheet, I can determine whether a resistor is needed and what value it should be.

dc42:
I suspect that the resistor you are using is much higher than 150 ohms, or that you have connected it incorrectly. Can you post a photo? Also, if you can post a link to the lcd datasheet, I can determine whether a resistor is needed and what value it should be.

The resistor is brown, green, red, and gold. I got the LCD working by the Arduino tutorial, and i'm not using a resistor ATM. The potentiometer changes the contrast, while adding a resistor removes the backlight.

That's a 1,500 ohm resistor. You need Brown, Green, Brown, not Brown, Green, Red.

darkdragon:
That's a 1,500 ohm resistor. You need Brown, Green, Brown, not Brown, Green, Red.

All I have is

Brown Green Red Gold
Brown Green Orange Gold
and
Orange Silver Orange Brown Gold

Unfortunately, all of those resistors are too high to use as a series resistor for the backlight. [EDIT: the first is 1.5K, the second is 15K and the third is 3?K, I think you misread Silver because it doesn't make sense in that position.]

If you have a multimeter, you can check whether the LCD includes a backlight or not. Disconnect the wires to pins 15 and 16 of the lcd, then measure the resistance between each of those pins and the LED A and K connections (these are the two soldered connections at one end of the LCD). If you find that each of pins 15 and 16 is directly connected to one of the LED pins, then there is no built-in series resistor, and you risk burning out the backlight by not using one.

It's obvious that you can't pass step one since you didn't follow it. You didn't connect LCD pin 1 and 2 to ground and 5V. Disconnect LCD pins 15 and 16 now.

Hello.
You can nearly spot the backlight connection pins at the right side of dpy.
If he's eager to continue, he dont need the light unless its environment is dark?

best regards

dc42:
Unfortunately, all of those resistors are too high to use as a series resistor for the backlight. [EDIT: the first is 1.5K, the second is 15K and the third is 3?K, I think you misread Silver because it doesn't make sense in that position.]

If you have a multimeter, you can check whether the LCD includes a backlight or not. Disconnect the wires to pins 15 and 16 of the lcd, then measure the resistance between each of those pins and the LED A and K connections (these are the two soldered connections at one end of the LCD). If you find that each of pins 15 and 16 is directly connected to one of the LED pins, then there is no built-in series resistor, and you risk burning out the backlight by not using one.

Congrat with Your arduino and display.

This guy is telling some about LCD if You understand english Tutorial 13 for Arduino: Liquid Crystal Displays (LCDs) - YouTube

In the tech. manual for display, You can read the typical voltage for the background light.
My display has maximum 4,6 volt and typical 4,2 volt ( You should try to achieve your display typical background voltage by connecting a serial resistor, as another poster said).

best regards

janeik:
Congrat with Your arduino and display.

This guy is telling some about LCD if You understand english Tutorial 13 for Arduino: Liquid Crystal Displays (LCDs) - YouTube

In the tech. manual for display, You can read the typical voltage for the background light.
My display has maximum 4,6 volt and typical 4,2 volt ( You should try to achieve your display typical background voltage by connecting a serial resistor, as another poster said).

best regards

I know you want to help but if you read my post and inspected the picture, you should conclude that the OP failed to power the LCD. Unless OP powers the LCD, there is no need for more discussion.

liudr:
I know you want to help but if you read my post and inspected the picture, you should conclude that the OP failed to power the LCD. Unless OP powers the LCD, there is no need for more discussion.

LIghten up a bit, it is supposed to be fun. :slight_smile:
I thought the tutorial video was actually pretty informative.
If you look at the tutorial it goes really slow.
Step 1 does not use pins 1 or 2 (controller power and ground).
It only hooks up the back light.
The first step is even called: "Power and backlight"

The only danger with the tutorial on ladyada's site is that it assumes
that the lcd does not need a current limiting resistor as it is geared
towards the lcd she sells.

Yep, the wiper is hooked up, in preparation for the next step:
"Contrast circuit", be we are still on the first step of getting the backlight
to work.

Zippyvinman,
that last resistor color pattern maybe it is really
orange, gray (not silver), orange, brown, gold.
That would make it 3830 ohms which is still too high for current limiting resistor.

Best thing to do if you are stuck and don't have an ohm meter to check
for a current limit resistor on the lcd and really want to start playing with the lcd "now",
is to simply disconnect the backlight and then
proceed without it. With the type of display you have you will be able to see
the pixels without a backlight.

You can then come back later and deal with the backlight.

--- bill