Help with LCD displaying black blocks

Hi all,

I’m new to the Particle community and IoT in general. My background is in software development but I have very limited knowledge of the wiring and electronics side of things.

I’ve had some minor success with a few basic projects and have recently undertaken the task of getting the Photon to work with a 16x2 LCD screen. I’ve been following these two pages to get setup:
Liquid Crystal Library?

I’ve had a bit of success but I’ve run into an issue that has me stumped. Basically I have power going to the LCD screen and have a potentiometer setup to set the text contrast but when I run the Spark-HelloSparky.cpp example all I see a black blocks rather than the expected text. What am I doing wrong?

I’ve attached a screen shot of the issue with a partial view of my wiring. I’ve tripled checked the wiring and it should match the wiring shown in Jon Gallant’s blog.

Any advice would be greatly appreciated

You will need to first solder the header pins to the lcd to ensure good connectivity.


Thanks for that, I was worried that simply hanging off the pins would be a bit ‘hacky’. I’ll solder the LCD and tell you how I get on.