Hi, I pulled apart an old laser printer and took out the LCD screen and the chip that it's attached to, which has 9 buttons and a green LED. I figure that if I can reverse engineer this thing, it'd be a neat place to start with learning some Arduino. My question is where do I start? Is reverse engineering something like this too complicated for a beginner? What would be the process that I go through to understand the circuitry of the thing? I figure that I need to start by understanding which pins control which buttons and LEDs, and which pin the ground is but it's not obvious to me how to do this.
Show also a picture of the back.
This is unlikely to be a self contained unit which you could hook up to an Arduino and demonstrate very much.
The most you may be able to do is read the buttons and light the led. If you are lucky, write something onto the screen.
To start a such a reverse engineering task, you’d first attempt to recreate the schematic diagram of that board. You’d use simple observation of the tracks and a multimeter and attempt to identify all the components.
Once you’ve got that far, you could then do further tests (example run a I2C scanner) against the display, if that looks like an appropriate test at that stage.
Judging by the 9 way ribbon connector and the visible components, the buttons are likely organized in a matrix and the screen has a serial interface.
6v6gt:
Show also a picture of the back.
This is unlikely to be a self contained unit which you could hook up to an Arduino and demonstrate very much.
The most you may be able to do is read the buttons and light the led. If you are lucky, write something onto the screen.
Thanks @6v6gt for the input, here's an image of the back of the board. You've given me a good starting point for my research. When you mention the 9 way ribbon connector, are you talking about the one at the top of the board, or the one connecting the LCD to the board? There are 18 pins on the top connector and then 12 on the LCD...