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

Nice bright display. Unfortunately it didnt last- it lost most of the characters. Now it is a 2x8 display. I restored the rating to 5 stars because further investigation showed it was an over voltage condition that damaged the display. Would recommend this product over the other sellers because the serial interface is already soldered in place, so saved a few minutes. Plus, a better price.

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

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 hooked this 20 x 4 line display up as my temperature monitor. Works great and in programming all you need to know is the lines you are displaying (4) and the max characters you display (20). I blew one with walking on my rug and zaping it with static discharge, now i get square characters.

price very good deliver fast come assembled

Easy to find existing libraries in Arduino

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.

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.

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.

I2C is the way to go to minimize the pin count used on your board. Love the contrast Black on Yellow display very bright and very easy to read, The Contrast control works great. Price point is about right for this product and Yes I will purchase more the next time I need more displays .