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

No complaints. Does the job. Everything works

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.

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.

Follow Up: I just received the 2nd screen that I ordered to replace the broken one. This one is defective as well. This time it is detected on the I2C bus 1/5th of the time if that, and when sending data to it it similarly only works a small percentage of the time. Most of the time is doesnt respond at all - just the white blocks on 2nd and 4th rows. I should mention that I2C sensors and an OLED screen on the same I2C bus (same pins, wires) work 100% of the time. Will not be buying screens from HiLetGo anymore. Go with another brand for a few dollars more. Did not work. I scanned all I2C addresses and it did not show up at all - tried different wires, different spots on breadboard, etc to no avail. I also tried sending data to the two addresses suggested by others - but nothing happened. All it would do when connected to power is show the backlight and two rows (row 2 and 4) of white blocks. Contract adjustment did not help.

Good product. Good seller.

I bought this display to use in a GPS clock that displays local time and date and UTC time and date. Here are my observations. 1. Its big! I should have read the specs more closely, but its much bigger than I expected. 2. The contrast is OK, but its nothing to write home about. 3. The viewing angle is very small. Once you get about 30-degrees off-axis, the contrast falls off rapidly. You have to be almost dead in front of the display to read it. 4. The default brightness of the backlight is very bright - too bright for me - harsh even. It lights up a room at night. I added a 330-ohm resistor to tone it down a bit. Otherwise, its a standard LCD display, and writing code for it is pretty simple. For what its worth, the hd44780.h display library is MUCH faster than other libraries (such as LiquidCrystal_I2C.h). I highly recommend it. I am undecided if I will use this display in my project. The viewing angle is just so small, and thats not great for a clock. A TFT display can be had for about the same price, and the viewing quality and versatility are much better. That being the case, I would not recommend this display.

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!

Display worked as expected. I had trouble initially setting up in code as I have only used 2x20s in the past. I sent an email to HiLetgo and they responded with all the info I needed. I highly recommend.

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.

Easy to find existing libraries in Arduino