2 Pack HD44780 1602 LCD Display Module DC 5V 16x2 Character Blue Blacklight

SEE BELOW for setup tips:Product is great - one of the two had a black speck underneath the screen, but when I contacted the seller to tell them and ask them how they would like me to proceed, they refunded my money for the entire order - fantastic support!Bummer that I only got one but that's how manufacturing goes sometimes. I will be purchasing more when I need them.- Connected up to Arduino Uno through YT vids and other resources (google will help with these)- Pulled some sketch code from Arduino site- Tested the LCD screenAT FIRST, I didn't realize there was a knob to turn with a screwdriver on the back. That is on the I2C bus (soldered to the LCD screen, and slightly tilted [normal]) and it controls the brightness of the LCD screen.Good luck and have fun!

There are 2 types of I2C chips on these "If you have the PCF8574T. the default I2C bus address is 0x27. If you have the PCF8574AT the default I2C bus address is 0x3F." More information here. Google "tutorial-serial-i2c-backpack-for-hd44780compatible-lcd-modules-with-arduino/" If you run the command "i2cdetect -y 1" the output will show you if it is 0x3F or 0x27. I followed this video guide to get this working with my Raspberry Pi Zero. Youtube search "Raspberry Pi - Mini LCD Display Tutorial" by TheRaspberryPiGuy. These screens are great value for money and are really easy to use.

This LCD Works Great for 5V Arduino Boards (and maybe some 3.3V boards)NO Instruction were includedNO software or demo scripts or links were included in the boxDoes not work as expected when powered by 3.3V to the LCD (5V is really needed for power)To get it working without instructions required more than an hour of frustration. The default address of this LCD was found to be 0x3F. I was able to find the address by running an I2C scanner script. Once you know the I2C address of the LCD display, you will need a script that is compatible with the chip on this LCD display and then you must enter the I2C address. The only script I could find that worked with this LCD was the LiquidCrystal_I2C library on GitHub and I installed it into my Arduino library. To set the LCD address properly in the Arduino script software, I changed a line of the script to readLiquidCrystal_I2C lcd(0x3F,16,2);The 0x3F is the address, 16 are the characters, and 2 are the number of rows of this LCD display.The second issue was that the LCD the characters do not work properly when run from a 3.3V source. When connected to a 3.3V source, the characters were dark on a dark blue background and not visible except at an extreme angle and with the pot on the back pushed past it's normal range. The work around was to power the LCD Vcc by the USB 5V power and thankfully the I2C pins on my 3.3V Arduino board are 5V tolerant, so the Arduino chip did not burn up. I also had to adjust the potentiometer on the back of the LCD display, to get the contrast right after applying 5V.I photo is attached and it looks good now that it is working and I hope you have a faster success than myself.-J Blaha

Two rows of 16 characters. Functions properly, but you will need to adjust the potentiometer every time you change the supply voltage. The display is located at 0x27 on the I2C bus. You can modify the lower three bits of the address by soldering a jumper (or even a blob of solder) across the A0, A1, and A2 pads next to the blue potentiometer. On an Arduino, use the LiquidCrystal I2C library (open the library manager, search for LiquidCrystal and install the I2C version) to drive the display.

I'm new to microcontrollers, so I'm teaching myself as I go along. I spent 2 days fiddling with these trying to get them working, not understanding what I was doing wrong. I was trying different libraries, swapping addresses, doing everything I could think of, and I couldn't get them working. Until I discovered that the contrast dial on the back control board, was apparently factory set to off; and my code & wiring had been working the whole time. When you get it, and first wire it up, & run the first Hello World, put a screw driver in the dial on the back, and turn up the brightness (I think mine was clockwise, when looking at the back of the board). By default for my 2 boards, both had the brightness of the lettering turned down to off. The back-light was in full glory, but text brightness was basically turned off.Once you get the text brightness/contrast turned up so that you can actually see the text, these boards work well, and the White-on-Blue color pallet looks good in my opinion.-Yurelle

I bought these for a rapid prototype project. The overall quality if the displays is quite good and I will probably buy more for future projects. Each display consumes a low enough current with the back light where I could still power the Arduino and display from my laptop USB 2.0 port. I don't have much experience with LCDs and had a little difficulty finding documentation for these but I did the following for my project.To get the displays to work, I ended up using a library from an instructables article called "Arduino I2C LCD Driver Library and PackMan"If you download the library, you should make the following changes in the examples:1: In all library examples, change LiquidCrystal_I2C_PCF8574 lcd(0x27,20,4); to LiquidCrystal_I2C_PCF8574 lcd(0x27,16,2);2: In the LCD_I2C_HelloWorld example, change lcd.print("Hello, world!"); to lcd.writeStr("Hello, world!");3: LCD_I2C_PCF8574_SingleDisplayFunctionality is a great way to learn how to use the displays but there are multiple locations in this example where they hard code 20 characters and 4 rows of text so some of the functions may not show up on the display unless you find and fix these.