I have done a lot of Arduino projects, including some using I2C. I decided to do some projects to display values on a display instead of using a serial port.
First I bought some 2 X LCD 1602 2 line display LCDs that have 16 pins. I was able to get this to work, but the wiring was ugly, so after a little research, I decided to get some I2C adapters for 1602 LCDs. I started by breadboarding and connecting everything to an Arduino UNO. I used code to check the I2C address and then tried using a demo program to display Something on the screen. I got nothing. After several attempts, I decided to solder the 16 pins for I2C adapter to the 1602 LCD display, and still nothing. No errors...nothing. I could prove that the Arduino was properly sending stuff to the I2C interface, but nothing displayed on the screen. In both instances above, I adjusted the variable resister a lot, but ...nothing.
I wondered whether there was some compatibility problem that I could not discover between the I2C adapter and the 1602 2 line display since I bought them from different sources.
So I decided to try another tack. I bought some OLED 128X 32 displays. I thought this would solve 2 possible problems;
- not getting the backlight resistance properly adjusted, and
- having the I2C adapter as part of the product, not worrying about compatibility problems
I wired up this I2C device downloaded appropriate Adafruit libraries and sample code. Again I have successfully tested the I2C interface and address. I have double checked wiring, and again, everything seems to work (Including Serial.println inserted code), but nothing displays.
I am getting frustrated. I would have thought that displaying stuff on an LCD would be a straightforward thing to do with Arduinos. I don't think I have had any other Arduino experience where I try to do such a simple straightforward thing, and get nothing.
I am not looking for sophisticated graphics or anything. I just want to display text. What is the most straightforward way to do this and not get caught with things that don't work and no easy way to debug the problem?
Also, if someone has any idea how I could step by step figure out either what is wrong with my 2 X 1602 and I2c adapter or my OLED display, it would be appreciated.