That did explain away why some of the sketches downloaded off the interned didn’t work. And, just typing “1602 LCD Module Arduino” into a search engine will return sketches for either, often without much explanation. This is of course significant, since you’d use two different libraries when communicating with the LCD: either you use the LiquidCrystal library (for “parallel” 1602 LCD modules), or the LiquidCrystal_I2C library (for 1602 modules with a parallel-to-serial converter). That’s pretty cool as it reduces the number of digital pins required from the Arduino board to just two (again, plus power and ground). Some 1602 LCD modules do, however, come with “a little red board” pre-soldered on, which essentially is a parallel-to-serial converter. To simplify things, the “basic” 1602 LCD module has a “parallel interface” – meaning, that it requires the use of several of the digital pins (6, to be precise) of an Arduino board, plus of course power and ground.

On the left below is a photo of two 1620 LCD modules I have laying around – they look pretty identical, right? However flipping them over, they look almost, but not quite, identical: one of them has a little red “board” riding on it. Unfortunately, there’s a little more to it than just what’s in the specification.Fortunately, one doesn’t need to memorise (or, even, read) all this to use it: there’s a library for that which is one.Serial vs Parallel?ġ602 is the model number for the LCD module – and, there are a ton of 1602 LCD modules out there – here’s an example of the specification of the 1602 LCD module (archived from ).

So we walked through it together, and (of course) got it to work – but, this walk-through revealed some easy-to-make misunderstandings from reading rand on publicly available tutorials. I thought I’d document those. The student had tried various Arduino sketches, downloaded off from various places of the Internet and which ought to work – but, which didn’t, much to both his surprise and frustration. The shield is a clever little combination of a 2 lines / 16 characters LCD display and 5 buttons, that snap on top of an Arduino Uno, and makes for a nice little development platform.

Arduino uno lcd datasheet