ESP 32 Project

Blinking LED Using Timer in MicroPython for ESP32 and ESP8266

In this project, you’ll learn how to Blinking LED Using Timer in MicroPython for ESP32 and ESP8266. Timers allow us to execute tasks at regular intervals without blocking the main code, making them ideal for periodic actions like blinking an LED. This project introduces you to timer initialization and the use of callback functions for time-based events.

Purpose of the Project:

The purpose of this project is to help you:

  • Initialize a hardware timer in MicroPython for ESP32 and ESP8266.
  • Use a callback function to toggle an LED at regular intervals.
  • Understand the concept of non-blocking timers for periodic tasks.

Data Types and Variable Table for Blinking LED Using Timer in MicroPython

Data Type Variable Name Description
Timer timer Represents the hardware timer object.
Pin led Represents the GPIO pin controlling the LED.
function toggle_led Callback function that toggles the LED on and off.

Syntax Table for Blinking LED Using Timer in MicroPython

Operation Syntax Example
Initialize Timer timer = Timer(n) timer = Timer(0)
Timer Callback Function timer.init(period, mode, callback) timer.init(period=1000, mode=Timer.PERIODIC, callback=toggle_led)
Stop Timer timer.deinit() timer.deinit()

Required Components for Blinking LED Using Timer

  • ESP32 or ESP8266 board
  • 1x LED
  • 1x Resistor (220Ω)
  • Breadboard
  • Jumper Wires

Circuit Diagram for Blinking LED Using Timer

        LED

         —–

         |—|—--> GPIO2  

         |   |     

         |—|—--> GND

          |

       220Ω Resistor

          |

         GND

 

Circuit Connection Table

Component Pin ESP32/ESP8266 Pin Explanation
LED Anode Connected to GPIO2 GPIO2 Controls LED using the timer callback function.
LED Cathode Connected to GND GND Ground connection for the LED.
Resistor Pin 1 Connected to GND GND Protects the LED from excessive current.

Warning:

Always use a 220Ω resistor in series with the LED to limit the current and protect the LED from damage.

Circuit Analysis for Blinking LED Using Timer:

The timer in MicroPython is used to toggle the LED at regular intervals. A hardware timer generates periodic interrupts that call the toggle_led function, which turns the LED on or off. This non-blocking approach allows the main program to perform other tasks while the LED blinks in the background.

Installing MicroPython and Libraries (If Needed):

No additional libraries are required for this project. The machine module in MicroPython provides built-in support for timers.

Writing the MicroPython Code for Blinking LED Using Timer:

import machine

from machine import Timer

 

# Initialize LED on GPIO2

led = machine.Pin(2, machine.Pin.OUT)

 

# Toggle the LED state

def toggle_led(timer):

    led.value(not led.value())

 

# Initialize a hardware timer to blink the LED every second

timer = Timer(0)

timer.init(period=1000, mode=Timer.PERIODIC, callback=toggle_led)

 

Running the Code and Checking the Output:

  1. Upload the code to your ESP32 or ESP8266 using Thonny or another MicroPython IDE.
  2. The LED will blink at 1-second intervals, controlled by the hardware timer.
  3. The timer runs in the background, allowing the LED to blink without blocking other tasks.

Explanation of the Code:

  • LED Initialization: The LED is set up on GPIO2 as an output pin.
  • Callback Function: The toggle_led function is called by the timer and toggles the LED on and off by changing its value.
  • Timer Initialization: The hardware timer is initialized with a period of 1000 milliseconds (1 second), and the toggle_led function is assigned as the callback.

Expanding the Project:

  1. Multiple Timers: Use additional timers to control multiple LEDs or other components at different intervals.
  2. User Input: Add buttons to change the timer’s period, allowing you to adjust the blinking speed dynamically.
  3. Complex Tasks: Use timers to control more complex processes like sensor polling or motor control.

Common Problems and Solutions for Blinking LED Using Timer:

Problem Solution
LED not blinking Ensure that the LED and resistor are connected properly, and that the correct GPIO pin is used.
Timer callback not triggering Check the timer initialization code and verify that the period and callback function are set correctly.
Timer behaving unpredictably Ensure that the timer mode is set to Timer.PERIODIC for repeated events.

FAQ for Blinking LED Using Timer:

Q: Can I use a different GPIO pin for the LED?
A: Yes, as long as the pin supports digital output. Modify the machine.Pin() initialization accordingly.

Q: How do I change the blinking interval?
A: Adjust the period value in the timer.init() function to change the interval between blinks.

Q: Can I use multiple timers at once?
A: Yes, ESP32 and ESP8266 support multiple timers. You can initialize additional timers with different IDs (e.g., Timer(1), Timer(2)).

Conclusion:

In this project, you learned how to blink an LED using a hardware timer in MicroPython for ESP32 and ESP8266. Timers are useful for running tasks at regular intervals without blocking the main code, which is essential for creating non-blocking, time-based events in embedded systems. This technique can be expanded to control multiple components and processes simultaneously.

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