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<\/p>\nThis is a quick example on how to use a bicolour LED with a NodeMCU.<\/p>\n
The bicolour LED has both red and green LEDs in a single package. There is a common cathode for both the red and green anodes. Applying a current to the red anode turns the red LED on. A current to green anode turns the green LED on. A current to both anodes creates yellow.<\/p>\n
The circuit is very simple. We wire the red anode to D1 on the NodeMCU, the green anode to D2, protecting them both with a 220ohm resistor. The cathode is wired to ground.<\/p>\n
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We program the NodeMCU using an Arduino sketch.<\/p>\n
int redPin = D1, greenPin = D2;\r\n\r\nvoid setup() {\r\n \/\/ set the pins to output mode\r\n pinMode(redPin, OUTPUT); \r\n pinMode(greenPin, OUTPUT);\r\n}\r\n\r\nvoid loop() {\r\n \/\/ red\r\n digitalWrite(redPin, HIGH); delay(500);\r\n \/\/ yellow\r\n digitalWrite(greenPin, HIGH); delay(500);\r\n \/\/ green\r\n digitalWrite(redPin, LOW); delay(500);\r\n \/\/ off\r\n digitalWrite(greenPin, LOW); delay(500);\r\n}\r\n<\/pre>\nIn the setup, we set D1 and D2 to both be outputs. We then turn D1 and D2 on and off in sequence every half a second to achieve a sequence of red, yellow, green, and off.<\/p>\n
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