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

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.

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.

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.

These are nice display modules with 2 wire I2c interface. Display is sharp and bright. Easy to read with or without the backlight. I tried to get a picture but my phone camera did not do it justice.

This works great with the i2clibraries.i2c_lcd class in Python. I tried it on 3.3v, but it needs the 5v. The backlight comes with a jumper cap, but I swapped it for a 10k pot, so now I have brightness control as well (see pic). And, its bigger than you expect, especially after using tiny oleds.

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

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!

Easy to find existing libraries in Arduino

You need female to male cables to hook it to the Arduino board. It powered up fine and shows the 4 lines you see in the picture of the product. However, I can not get it to write to line 4 ; lines 1,2,3 work fine but anything to line 4 over writes the data on line 2 ????? One day later and nothing will display; but the backlight is on and rows 1 and 3 have dark cursors in every column. Adjusting the POT does nothing. Got a replacement unit and it does the same thing; didt even show the original splash screen. Someone else had this same problem with two units. Arduino board works fine with the 16x2 screen that came with the kit. I give up.

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.