Send out 3 bytes x 506 LEDs once a second or whatever your display change time is. Be a lot easier to wire them all up, just one long string of daisy chained parts.Įach one will need 20mA for Red or Green only, and up to 40mA for Blue+Green.įor an arduino library to control them. In a common cathode RGB LED, the cathode of the internal LEDs are all connected to the external cathode lead.
#Led cathode serial#
You send it 3 bytes of serial data, it takes care of turning on the appropriate color, 8 bit PWM per color. LED display using common cathode technology, its energy-saving effect can reach 30 to 75, greatly reducing the power consumption, and can save a lot of electricity expenses every year. Diodes have a minimum threshold voltage (or Vth, usually around 0. Diodes are intended to conduct current from the anode to the cathode. The terminals of a diode are called the anode and the cathode a schematic symbol for a diode is shown in Fig. Say you used 40mA (the output is pulsed at 800 Hz), then a 6A supply.Īnother option would be WS2812B, which are RGB LEDs with a controller built in. Why is the heat of the common cathode LED display lower Cold screen special common cathode power supply mode, making the LED display work process produces less heat, temperature rise in low degree. Diodes and LEDs Diodes Diodes are two-terminal semiconductor devices that conduct current in only one direction. It refers to the common cathode method to drive the LED display and accurately distribute the current to the R, G, and B chips. MAX7219 turns on 8 LEDs at a time and needs 160mA or more at 20mA/LED (depending on brightness), Green+Blue = 16 * 160mA = ~3A power supply. The common cathode power supply method is a technical solution based on the improvement of the common anode structure to achieve energy saving of the LED display. You wouldn’t have to deal with multiplexing to make yellow, just turn on blue & green at the same time. Then we could work some math: say you were using MAX7219 to control the LEDs, which can control 64 LEDs each: 509/64 = 7.95, so 8 MAX7219s for each color. If you had RGBs that were 3 separate LEDs in a package, that would make life a lot simpler. Coliao 6pcs MAX7219 Dot Matrix 8x8 LED Display Module MCU 5V Control LED Matrix Display Module MAX7219 88. The problem with RGB is the awkwardness of manipulating them. Oiyagai 10 Pcs Common Anode 10-Pin 1 Bit 7 Segment 0.56' Red LED Display Digital Tube. To control each color, you need to apply a HIGH signal or VCC to the red, green, and blue leads and connect the anode lead to the negative terminal of the power supply. I count 506 LEDs there, so 1518 elements to control. In a common cathode RGB LED, the cathode of the internal LEDs are all connected to the external cathode lead. So you need to individually control all the RGB LEDs then.Ĥ00-600 = 1200-1800 control pins, unless you have some way to multiplex them.
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