ESP8266 NodeMCU Interface – LED

LED ON/OFF

Note : Assume the pin GPIO-5 is a LED (NodeMCU pin map is 1)

• Set LED Mode
  • Set LED pin (gpio-5) as output using gpio.mode(pin, mode [, pullup])  function.
  • Example :  gpio.mode(1, gpio.OUTPUT)
• Turn LED ON
  • Set LED pin (gpio-5) HIGH using gpio.write(pin, level)  function.
  • Example : gpio.write(1, gpio.HIGH)  or gpio.write(1, 1)
• Turn LED  OFF
  • Set LED pin (gpio-5) Low using gpio.write(pin, level)  function.
  • Example : gpio.write(1, gpio.LOW) or gpio.write(1,0)

LED Blink Using Timer

• Required NodeMCU Modules (Firmware) GPIO Module, Timer Module
• Required Hardware ESP8266 with Programmer (or)  NodeMCU Dev Kit, LED- 3v3 or 5v,
• Required Software Tools ESPlorer IDE Tool

ESP8266 with LED Connection Diagram

-- http://www.ArunEworld.com/embedded/ESPressif/ESP8266/ESP82266_NodeMCU
--[[ Required NodeMCU Modules
 Timer Module
 GPIO Module
]]--

LED_Pin = 1 -- GPIO-5
LED_Blink_Time = 1000 -- ms
gpio.mode(LED_Pin, gpio.OUTPUT)
local function Blink()
 if ( 0 == gpio.read(LED_Pin)) then 
  gpio.write(LED_Pin, gpio.HIGH)
 elseif( 1 == gpio.read(LED_Pin)) then 
  gpio.write(LED_Pin, gpio.LOW)
 end 
end

tmr.alarm(0,LED_Blink_Time,1,function() Blink() end)

Follow steps

• Connect the circuit as per the connection diagram
• Save the above code as “AEW_LED-Blink.lua”
• Open ESPlorer and upload the file “AEW_LED-Blink.lua”
• Run the file  [ dofile(“AEW_LED-Blink.lua”) ]
• Done.!(LED will Blink based on blink time)

LED Blink uisng While loop and Timer delay function

• Use

  -- http://www.ArunEworld.com/embedded/ESPressif/ESP8266/ESP82266_NodeMCU 
  --[[ Required NodeMCU Modules Timer Module GPIO Module ]]--
  LED_Pin = 1 -- GPIO-5
  LED_Blink_Time = 1000 -- ms
  gpio.mode(LED_Pin, gpio.OUTPUT)
  
  while true do
      tmr.delay(1000000)
      if ( 0 == gpio.read(LED_Pin)) then
          gpio.write(LED_Pin, gpio.HIGH) 
      elseif( 1 == gpio.read(LED_Pin)) then
          gpio.write(LED_Pin, gpio.LOW)
      end
  end
  

   

LED Fade using PWM

• Use this code

  pin = 1
  ------ PWM setup --------------
  pwm.setup(pin, 999, 512)    -- pwm.setup(pin, clock, duty) | set pin index 1 as pwm output, frequency is 100Hz, duty cycle is half.
  
  pwm.start(pin)          -- pwm.start(pin)
  duty = 1000
  
  for i=1000,0,-1 do
   --print(i)
   duty = i
   pwm.setduty(pin, duty)         -- pwm.setduty(pin, duty)
   tmr.delay(1000)
  end
  

   

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