Thus, we need to find another way to work this out. Because of we are controling rows and columns by simply shifting values into the shift registers (the previous example will light up all LEDs in the first column, and if the LEDs are not the same color or voltage requirement, it would not work at all). In order to light up the first LED of the matrix (row index 0, column index 0), then we need to shift out these values to our shift registers:Īnd yes, the GND REG register active in low, this mean we need to turn of an output and turn it on on the other shift register in order to make a LED work.īut, if we want to use this method in real time, we won't be able to control LED by LED. The LCD Display and the buttons are optional. cathods connected with anodes and verse versa), just keep in mind to connect the positive termenals of the LEDs with the VCC REG, and the negative terminals with GNDs REG. Note that in this image the LEDs are connected wrongfully (i.e. Let's connect the 8 anodes (+ termenals) with the output pins of another 74HC595 shift register. Let's connect the 8 cathodes (- termenals) with the output pins of a 74HC595 shift register. That means we would have 8 termenals of anodes (all positive of cource) as columns. That means we would have 8 termenals of cathodes (all minus of course) as rows.įor each column, all anodes (+ terminals) of LEDs are connected together. In this project, all 64 LEDs (regardless of the colors and voltage) can be light in one time without problem, and acts like it is one LED active!įor each row, all cathodes (- terminals) of LEDs are connected togather. But if we want to connect 8 LEDs with different colors and voltage requirements, it might not work with 5 v source. Regardless of the LED color and voltage requirement of that LED, if one LED is connected to 5 V source with 220 Ohm resistor, it would work fine. We have of course 8 x 8 (64) LEDs arranged in 8 rows and 8 columns. Ok let's talk first about the idea and how it works.