HiLetgo 2004 20X4 LCD Display LCD Screen Serial with IIC I2C Adapter Yellow Green Color LCD for Arduino Raspberry Pi

Bought two screens and thought one was not working. HiLetgo was very quick to offer technical assistance. It turns out I just got two screens with different I2C addresses and I was trying to use the same address for both. I am now very happy with both. FYI the addresses for my screens were 0x27 and 0x3f. Or if you are smarter than me you can look up the PCF8574 datasheet and probe pins A0, A1, and A2 to determine exactly what your address is.

Worked as expected.

It merely performs the expected functions that it should as marketed. It is a cost-effective solution which can be quickly attached to Arduino (I use custom 4-line ribbon to group and distribute SDA SCL and assure proper power inputs to the four-pin parallel-to-serial add-on soldered to the back of the 20 x 4 display. Its a snap to apply the LCD to an AT-mega.

I much prefer these green LCD displays with the yellow backlight because I can read them with the backlight off which saves about 40+ ma. Some of the projects put the Arduino to sleep as I am trying to minimize power draw. The blue LCDs are not really readable when the backlight is off.

Displays seemed OK once the correct address was found. I ordered 2 in Feb. 2023, and both of them were at address 0x3F. This address is not even listed in the chart of possible addresses provided in the listing! I unsuccessfully tried all the addresses Id seen in previous reviews. (At that point I hadnt yet seen where a previous reviewer had reported that one of his two displays was found to be at 0x3F) I had to resort to an I2C address scanner for the Arduino that I found online. Note that one of the addresses the scanner reports may be the Arduino itself. Make a note of any addresses found, then unplug the display and scan again. The address that is now missing will be the displays address. Hope this helps someone.

Replaced a 16x2 Lcd with this and I love it! Installing and modifications of the arduino code was a breeze. Used the LiquidCystal_I2 library. Example sketch included a scanner for finding the address. (0x27 on mine). If you are using a 16x2 this is a great upgrade!

I was skeptical that a yellow backlit LCD would be visually appealing, but the contrast between the yellow background and the black letters is the best I have seen of any other color combination. It is amazingly clear and bright. The unit I received has an I2C address of 0x27 just like the product description states. The LiquidCrystal_I2C and LiquidCrystal_PCF8574 libraries from GitHub both work equally well with this unit, so you can use either one. HOWEVER, both libraries turn the backlight off by default so having the backlight jumper on the I2C interface isnt enough, you must ALSO use lcd.setBacklight(1) in your program to activate the backlight.

Plugged it in to my Arduino, and it works with the standard arduino library. No problems whatsoever.

Works fine. I did not need, nor want the feature of the IIC board, so I removed it and used the display as a parallel type.

Shipped fast, next day in my case, was package in its own box making it very well protected. I was able to hook it up a have some examples running on it in minutes! This will be perfect for a Time. Temp, Pressure display project in my shop! The extra two lines this display provides may come in very handy for this!