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In this lab you will u

se the LED drive shield to control an LED display using the Arduino and then fabricate your own OLED.

Prelab Questions

Refer to the links, schematics, source code, etc provided to answer the following exercises.

  1. Compare and contrast the direct drive scheme and the MAX 7219 drive scheme. What are the advantages and limitations of each drive scheme?
  2. Examine LED_Direct_2010.pde and LED_7219_2010.pde. What does each program do? How does each program address an individual LED? Modify these programs to display useful information.
  3. List some advantages and disadvantages of OLED displays.
  4. The organic layers will be deposited using a thermal evaporator in a nitrogen glovebox. Why is it necessary work in a nitrogen environment?
  5. Briefly describe the process of thermal evaporation. Why is it necessary to perform the evaporation under vacuum?
  6. The material layers for the OLED are shown below. Briefly describe the function of each layer and draw the band diagram for the OLED.


Take a look at LED_Matrix.pdf. The pin configuration of commercial LED matrices can be confusing. For example, if you want to turn on the pixel in the first row and first column you have to use pin 9 and pin 13 (or the first and fifth pin on one side of the matrix). Wouldn't it be easier if you could use the first pin on one side (the row side) and the first pin on the other side (the column side)? Now you can! Your kit includes an adapter board to change the pinouts. Here's how to assemble it. Solder male pin headers into the row and column locations (See picture for orientation). Find pin 1 on the LED matrix and align it with P1 on the board. Put the matrix on the board and solder it. Note: Pin 1 is on the side of the LED with the notch.

The rest of the shield is easy to assemble. Solder the socket for the MAX7219, female headers for the LED matrix, the two capacitors (CAREFUL - the 10uF cap is polarized and the negative terminal is marked by a - on the board), and the 47k potentiometer. Note: This year's kit do no include a socket. Solder the MAX7219 directly to the board. Make sure IC is oriented so that the notch on the IC matches the notch on the silkscreen. This year's kit also include a round instead of square blue potentiometer.

Now insert the MAX7219 and the LED matrix and you're good to go! The orientation of the LED matrix is important. If your display is not working correctly, rotate the matrix 180 degrees.

OLED Display in Action

Useful Links

Libraries required for MAX7219
Subpages (1): OLED Files