If you want to add some visual output to your Arduino projects, you'll need a display. If you need only little to display, the LCD 1602 is a quite good solution. But you'll waste about 8 Pins on your Arduino for the display to get working. Luckily there exists a I2C adapter that you can solder right onto the pins of the display. So all you need to connect are the I2C pins, a good library and little of coding.
If you already have the I2C adapter soldered onto the board, wiring is quite easy. You should usually have only four pins to hook up. VCC and GND of course. The LCD display works with 5 Volts. So we go for the 5V Pin. The Arduino Uno and Nano can handle the current need for this display. SDA (data line) to analog 4 on your Arduino Uno or Nano. And SCL (clock line) to analog 5 (other Arduinos or ESP might have different pins).
- Did you remember to call the init()-method of the library?
- Did you turn the backlight on?
- Have you tried to adjust the contrast with the potentiometer on I2C adapter?
- Did you check the I2C address? (use the i2cdetect sketch)
You can search on eBay for LCD1602 I2C. You'll get plenty of results.
Or, here are some direct links to Amazon: