Experimental Results

Latch up triggered

The result signal of the Leds display when the changes of animations produced. I had used the experimental circuit results to prove that how the animation working in the circuit based on the signal from result in oscilloscope. The first signal is triggered to latch up new data for column. The second signal is activated to low for turning on the column for led matrix. The frequency for one frame is 30 ms.

Signal from driver circuit

The first signal is generated from driver circuit. The signal is set to active within 5 ms and exponentially going down within 20 ms. The timing is crucial to ensure the Led matrix is protected from over current.

Circuit of Led Animation for Experiment

Character N

Character J

    Super bright LED

These super bright LEDs will be display strong brightness for display on boards. When the 12VDC supply is given from the driver circuit, this display leds will be active and will display animations. The matrix theory configuration used in this design allows all 448 leds to be controlled with a total of just 71 switches. The arrangements of leds however impose restrictions on the combinations of leds that maybe switched on simultaneously. To effectively control the leds display, a multiplexing technique must be employed. With the frame repetition rate at about 50 frames per second, the human eye fails to keep pace with the rapid switching and interprets the light output as constant; an effect known as “persistence of vision”. Multiplexing considered preferable to the alternative method which involves driving each led from a separate latch.

Driver circuit

In this project, the driver circuit is the main circuit to make any animation display on leds. The programming sent to the microcontroller board then, it sends to the driver circuit to produce animations of leds display. Each column of Leds requires a current limiting resistor that was connected in series. To compensate for the multiplexing system and to ensure a high brightness display, the leds are operated at 100mA, over three times their normal maximum current rating. The row switches are prevented from being turned on continuously, thus protecting the leds from damage. When the latch output goes low, diode holds its side of capacitor at 0V ensuring it is discharged and ready for the next pulse.