Arduino: Get the Character LCD to work

Finally I managed to get my 20x4 Character LCD to work.

Someone in Arduino Forum mentioned that the most common problem in using LCD is connection related. This is proven true once again.

Just after getting the LCD I solder pin headers to the PCB and I thought the connection would no longer be a problem. However, after trying several hours using either Arduino Liquid Crystal Library or my hand-written code, I failed to make the LCD displaying anything. I started thinking it was the LCD's problem and trying to contact the seller from eBay to replace the module.

In the last try, when I was using multimeter to measure the voltage between GND and V0, surprisingly I found that when I put the probes on GND and V0, there's something displaying on the screen, although very dim.

It was very obvious the problem is the connectivity of V0. I had thought the soldering quality is pretty good, but seems it is not :-(. After re-solder that header , the "Hello World" finally displayed on the screen.

Now I will start writing my own LCD library. After all, the best way to understand how one thing works is to try it by yourself, right?