Los LED pueden utilizarse tanto para iluminar como para indicar. También pueden disponerse como indicadores de 7 segmentos o como diminutos píxeles en una pantalla OLED (LED orgánico).
Este capítulo contiene recetas relacionadas con la alimentación y el control de los LED, así como para utilizar una pantalla con un Arduino o una Raspberry Pi.
14.1 Conectar los LEDs estándar
Problema
Quieres conectar un LED estándar de bajo consumo a una patilla GPIO, pero no estás seguro del valor de resistencia en serie que debes utilizar.
Solución
Ya en la Receta 4.4 viste cómo un LED necesita una resistencia en serie para evitar que fluya demasiada corriente. Demasiada corriente acortará la vida de un LED, pero lo más importante es que puede dañar o destruir el pin GPIO de Arduino o Raspberry Pi que controla el LED.
Conecta tu LED a una patilla GPIO como se muestra en la Figura 14-1 y luego utiliza la Tabla 14-1 para seleccionar un valor para la resistencia en serie.
Figura 14-1. Conectar un LED a una patilla GPIO
Tabla 14-1. Valores de las resistencias de la serie LED
Infrarrojos
Rojo
Naranja/Amarillo/Verde
Azul/Blanco
Violeta
UV
Vf
1.2-1.6V
1.6-2V
2-2.2V
2.5-3.7V
2.7-4V
3.1-4.4V
3,3V GPIO 3mA
1kΩ
680Ω
470Ω
270Ω ...
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