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

As an I2C device this was a no brainer and didnt consume any pins on my Arduino since the I2C bus is shared with several other devices. Once you adjust the potentiometer for the brightness it is very nice to read. It needs a different library than its 16x2 cousin but that was a breeze to find and install.

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.

Great product and works as designed. One screen came with a loose connection on the contrast potentiometer. At first one of the screens would not display the text and after looking into it I could get the I2C address but it wouldnt display any text. The green back light was fine and after testing the contrast pot I found that it was soldered enough, so I added solder and it works great now. Good price!

Was a little skeptical having read some reviews regarding poor solder connections, especially as the pictured device in the product description clearly shows solder bridges on the I.C. so I inspected it very carefully before proceeding. Workmanship as good as other quality and expensive components. Everything worked as advertised. The LED jumper disables the back-light and the display contrast is very clear. I also ordered the 2 extra I2C boards from the same vendor (Hiletgo) and both tested perfectly. Same results on other devices from them.

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.

Amazing product

I ordered two, weeks apart, and got two different products. The first one was great, clear, bright, high speed display updates, and good contrast and viewing angle. The second one looked very similar but the display was a little taller, and unfortunately has a spot in the backlight, the display is dim, updates slowly, and the viewing angle is not good. I want another one like the first one. Update: I have purchased three of these now and two are slow and dull with lousy viewing angle and contrast. I want another one of the good ones!!

Easy to find existing libraries in Arduino

No issues with this. Using it with Arduino Uno. Almost plug and play.

It works nicely and seems to be good value for the low cost. I had to play around finding the right library file to get it to work-the one on Last Minute Engineers works fine, and they have a nice tutorial to help get it running.