lcd display schematic for sale

TFT LCD panels always have a controller in there which is a CoG (chip on glass) type IC planted on to the panel to drive the rows and columns. The chip has referenace values and tables to drive the display to get the desired contrast and bias voltage needed to control the LCD pixels properly. Incorrect values can cause the panel to look low contrast and weak, or in the other extreme case cause permanent damage to the panel.

In addition to this, the LCD manufacturer configures the CoG LCD controller to use certain bias voltages that match the LCD panel characteristics (all LCD panels are not exactly the same). Here is an example from a 7″ display datasheet (ER-TFT07-2) with RGB interface.

After much thought, I decided to use an Atmel ATmega168 AVR microcontroller to drive the display.  I realize that this raises the technical level of this project significantly, but I have been wanting to feature an AVR project on the site and this is a great opportunity.  The truth is that an Arduino would work just as well and it shouldn’t be too difficult to port this program to an Arduino sketch.  (The Arduino is built with the same ATmega168 microcontroller, after all.)  If anyone does this, let me know and I’ll post a link to your version of the display.

I recommend following a tutorial or two and getting a simple blinking LED example working on your AVR before building the LCD display.  That way you can be sure your programmer, development environment, breadboard, etc are working first.

Special thanks to Peter Fleury for his excellent LCD library, which saved me from reinventing the wheel!  He also has another page about interfacing LCD displays to an AVR.

Assembling the circuit on the breadboard is pretty straightforward.  Here’s a photo showing all components of the setup.  The router is shown above with the serial port wired to the breadboard (the RX line is floating as we’re not using it yet).  The USB AVR programmer is on the right, where it is also functioning as a 5V power supply for the circuit. Make sure the 2-pin jumper on the USBTinyISP is installed, this enables the +5V supply.  The LCD is shown displaying the current stream name (DI.fm).

Here is a closeup of the components installed on the breadboard to show how I did things, feel free to experiment with the placement of components.  As long as you follow the schematic the circuit should still work.

Connect the USBTinyISP to your computer with the USB cable and to the breadboard with the ISP cable.  The green light on the programmer should be on, indicating it is ready, and the backlight of the LCD should be lit, indicating that the breadboard is getting power.

If everything went well, the LCD display firmware is now loaded into the ATmega168 and the circuit is ready to go.  If not, double check your connections and take a look at the help! page for the USBTinyISP.

Once the stream starts playing, execute the display.sh script we created in part six.  Within a few seconds, if everything is working, you should see the stream name on the display, followed by the artist and name of the current song.  Congratulations!

Here is a video of the LCD display in action, including the horizontal scrolling feature to show information that is too wide to fit within the visible area of the display: