LCD Display installed on BeagleBone Black
LCD Display showing buttons and labels
LCD Display showing applications
4D Systems 4DCAPE-43T LCD Display for the BeagleBone Black
I decided to play around with an LCD display for my BeagleBone Black. The one that I chose is the 4DCAPE-43T LCD by 4D Systems (touch screen version). They have 2 versions, one with a touch screen and one without a touch screen. The one without a touch screen is the same number except without the "T" at the end. When I opened the box, there were no instructions included.
My first concern was that I be able to connect it correctly to the BeagleBone Black. I looked at the back of the LCD printed circuit board and found a silkscreen outline of the BeagleBone Black board. If the BeagleBone board is aligned with that outline, there is no way to connect it wrong.
There are several push buttons along the bottom of the LCD cape. Starting from the bottom left to right, they are labeled left, right, up, down, and enter. These are used to move around the display much as a mouse would do. To the right of the LEDs (power and user) are two more push buttons. The one nearest the LEDs is the reset button, and the other is the power button.
I wondered how easy or hard it would be to set this up and get it to work without any instructions. There are two jumpers on the back side of the LCD for configuring the cape address. Since I didn't have any other capes installed, I just left them as setup (lowest address). I then plugged the LCD display on the Beaglebone Black board, connected it up to an external power supply and turned the power on. Immediately the power LED glowed a bright green. I could see the LEDs on the BeagleBone start their boot up sequence. I watched the LCD display expectantly, and soon I saw the little wait symbol on the LCD screen that I was used to seeing on my big monitor as Angstrom linux boots up. Soon, the complete LCD display showed what I am used to seeing on my big monitor.
I first played around with navigating the display using the push buttons. As expected, they move the arrow pointer around the display, and when over an icon, if the enter button is pressed, the operation represented by the icon is executed. Pretty cool, and much easier to get working that I thought it would be.
Next I started playing around with the touch screen. Placing a finger over an icon and pressing it slightly causes the arrow pointer to move to the icon. Tapping the icon causes the operation to be executed. I have large fingers, so I sometimes found it hard to see exactly where the arrow was when I pressed. The idea occurred to me to make a stylus of some sort that would be smaller so I could better see what I was doing.
I took an old wooden chopstick, and put it in a pencil sharpener so that it had a point on it. To prevent damage to the LCD display, I took a file and rounded the tip so it was not sharp at all. Much to my surprise, this worked very well. I did find that the arrow pointer did not exactly match the spot where the stylus was pointing, but was instead a little bit below and to the left of the stylus.
I did find that navigating around
using the home made stylus with the touch screen was much faster than trying to navigate by using the push buttons!
I did not try using this LCD display with a keyboard attached to the BeagleBone as that was not my intended use for the LCD display. My primary use is for portable applications where the programs do not require any keyboard input, but only a way to navigate around a preset menu or menus in a developed program. It looks like it will work very well for this intended application.