Circuit's Blog :Return to Blog
Homemade LED Matrix
The project illustrates the assembly of a LED matrix display made in 16×24 Green SMD LED matrix.
The matrix contains 16 rows which are controlled by a 4:16 de-mux using only 4 I/O pins. Two 8-channels Darlington arrays were combined with the de-mux in which the perfect interface to control all 16 rows is provided. Three 8-output shift registers were strung in order to sink the columns and each shift register is rated to handle the 8 LEDs current which can possibly be ON at one time.
There a 3 green LEDs, 3 push buttons, ISP header, and TTL header that are featured in this project. Since the output pins on the chip are not exactly in a row, all the shift register outputs are criss-crossed for assisting in board layout. When the board is put together, the bunch of air-wires is manually jumped.
When the code is in operation, a 2D array 16×24 stores the value for each pixel. The initialization of the ports starts the code which initializes the timer. The buffer is used to write all the high level functions which will lead to a double buffered display during the shifting process.
Click here to see the rest of the project.