![\"ESP32](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2024\/11\/ESP32-Light-Sleep-and-wake-up-sources.jpg?resize=1200%2C675&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nTable of Contents<\/strong><\/p>\n\n\n\n In this tutorial, we’ll cover the following topics:<\/p>\n\n\n\n This tutorial focuses on programming the ESP32 using the Arduino core. Before proceeding, you should have the ESP32 Arduino core installed in your Arduino IDE. Follow the next tutorial to install the ESP32 on the Arduino IDE, if you haven\u2019t already.<\/p>\n\n\n\n The ESP32 offers several power-saving modes: modem sleep, light sleep, and deep sleep. We covered deep sleep in great detail in a previous post<\/a>.<\/p>\n\n\n\n You can compare the different modes in the following table from the ESP32 Espressif datasheet.<\/p>\n\n\n Unlike deep sleep, which fully powers down the CPU and most peripherals, light sleep retains the CPU’s state and keeps RAM data intact. This means program variables and states are preserved, allowing the ESP32 to resume tasks almost instantly upon waking. <\/p>\n\n\n\n This means that when the ESP32 wakes up, it will resume the code where it left off before going to sleep (contrary to deep sleep which runs the code from the start). Additionally, light sleep mode supports more wake-up sources like GPIO wake-up and UART wake-up.<\/p>\n\n\n\n The ESP32 Espressif datasheet<\/a> also provides a table comparing the power consumption of the different power modes.<\/p>\n\n\n In terms of power consumption, light sleep consumes less than active mode, but more than deep sleep.<\/p>\n\n\n\n Light sleep is ideal for applications that need moderate power savings but must still respond quickly to certain events or interrupts, such as temporarily inactive sensors that periodically check data.<\/p>\n\n\n\n Putting the ESP32 in light sleep mode is super simple. After setting up the wake-up source or sources, you just need to call the esp_light_sleep_start()<\/span> function.<\/p>\n\n\n\n After that, the ESP32 will wake up when the required wake-up source(s) is triggered. When the ESP32 wakes up, it will return to where it was in the code.<\/p>\n\n\n\n After putting the ESP32 into light sleep mode, there are several ways to wake it up.<\/p>\n\n\n\n To disable previously enabled wake-up sources, use the esp_sleep_disable_wakeup_source()<\/span> function and pass as argument the wake-up source you want to disable. If you want to disable all wake-up sources pass ESP_SLEEP_WAKEUP_ALL<\/span> as argument.<\/p>\n\n\n\n A list of the wake-up sources can be found here: sleep wake-up source argument<\/a>.<\/p>\n\n\n\n In this section, we’ll show you how to put the ESP32 in light sleep mode and wake it up after a defined interval.<\/p>\n\n\n\n To wake up the ESP32 after a predetermined period, you need to set up a timer wake-up using the esp_sleep_enable_timer_wakeup()<\/span> function. Pass as argument the time in microseconds.<\/p>\n\n\n\n The following example will put the ESP32 into Light Sleep mode. The ESP32 will wake up every 10 seconds.<\/p>\n\n\n View raw code<\/a><\/p>\n\n\n\n This example turns an LED on when the ESP32 is woken up and increases a counter<\/span> variable in each loop. This example demonstrates that the ESP32 RAM retains data, so variables and program states remain intact when the ESP32 wakes up. <\/p>\n\n\n\n When it wakes up, it returns to where it was in the code (contrary to deep sleep<\/a> that starts running the code from the beginning).<\/p>\n\n\n\n Let’s take a quick look at the relevant parts for light sleep with timer wake-up.<\/p>\n\n\n\n In the setup()<\/span>, we call the esp_sleep_enable_timer_wakeup()<\/span> function to enable timer wake-up. We pass as an argument the sleepTime<\/span> variable(10000000 microseconds = 10 seconds).<\/p>\n\n\n\n The esp_sleep_enable_timer_wakeup()<\/span> function returns ESP_OK<\/span> if timer wake-up was successfully set up. We check that in the following lines. <\/p>\n\n\n\n In every loop()<\/span>, we increase the counter<\/span> variable.<\/p>\n\n\n\n Light up the onboard LED for two seconds.<\/p>\n\n\n\n And we put the ESP32 in light sleep mode by calling the esp_light_sleep_start()<\/span> function.<\/p>\n\n\n\n When the ESP32 wakes up from sleep, it will continue running the code. So, after waking up, it will print the following message.<\/p>\n\n\n\n In every loop()<\/span> and wake-up cycle, the counter<\/span> variable increases. This proves that the ESP32 can retain the values of variables during light sleep.<\/p>\n\n\n In this section, you’ll learn how to put the ESP32 into light sleep mode and wake it up with an external wake-up, in this case, a pushbutton. Any GPIO that is an RTC GPIO can be used to wake up the ESP32.<\/p>\n\n\n\n There are three different ways to use external wake-up with light sleep: the ext0 <\/strong>method, the ext1 <\/strong>method, and the GPIO <\/strong>wake-up. We’ll take a look at each of them.<\/p>\n\n\n\n The ext0<\/strong> external wake-up allows you to wake-up the ESP32 when an RTC GPIO is set to a predefined state. RTC peripherals are kept on during sleep if this wake-up source is requested.<\/p>\n\n\n\n To use this wake-up source, use the esp_sleep_enable_ext0_wakeup()<\/span> function and pass as argument the GPIO number in this format GPIO_NUM_X<\/span> (in which X corresponds to the GPIO number), and the level (0<\/span>=LOW, or 1<\/span>=HIGH).<\/p>\n\n\n\n For example:<\/p>\n\n\n\n Note:<\/strong> you can only use pins that are RTC GPIOs<\/strong> with this wake-up source. Here\u2019s a list of the RTC GPIOs for different ESP32 chip models:<\/p>\n\n\n\n Recommended reading:<\/strong> ESP32 Pinout Reference: Which GPIO pins should you use?<\/a><\/p>\n\n\n\n Recommended reading:<\/strong> ESP32-S3 DevKitC Pinout Refence Guide: GPIOs Explained<\/a><\/p>\n\n\n\n Here’s a simple example using light sleep with external wake-up ext0<\/strong>. This example wakes up the ESP32 with the press of a pushbutton. Every time it wakes up, it turns on an LED for five seconds and increases the counter<\/span> variable.<\/p>\n\n\n\n To test this example, wire a pushbutton to the ESP32 GPIO 27 as shown in the picture below (because we’re using an internal pull-down resistor, we don’t need to add to the the circuit).<\/p>\n\n\n After wiring the circuit, you can upload the code to your board.<\/p>\n\n\n View raw code<\/a><\/p>\n\n\n\n First, define the GPIO that will be used for wake-up. In this example, it’s GPIO 27.<\/p>\n\n\n\n In the setup()<\/span>, we define the pushbutton as an input with a pull-down resistor.<\/p>\n\n\n\n Then, we enable the ext0 <\/strong>wake-up source on GPIO 27. We pass 1<\/span> for the level, which means it will wake-up the ESP32 on a HIGH signal\u2014because we’re using a pull-down resistor, it will receive a HIGH signal when you press the pushbutton.<\/p>\n\n\n\n In the loop()<\/span>, we increase the counter<\/span> variable, light up the onboard LED for five seconds and finally, call the esp_light_sleep_start()<\/span> to put the board into light sleep mode.<\/p>\n\n\n\n Upload the code to your board. Open the Serial Monitor at a baud rate of 115200. Press the pushbutton to wake up the ESP32.<\/p>\n\n\n\n Every time you press the pushbutton, the ESP32 will wake up, print, and increase the counter<\/span> variable, light up the onboard LED for five seconds and will go back to sleep.<\/p>\n\n\n You can wake-up the ESP32 using multiple GPIOs with this wake-up source. The ext1<\/strong> wake-up source is implemented by the RTC controller. So, RTC peripherals and RTC memories can be powered off in this mode.<\/p>\n\n\n\n Use the esp_sleep_enable_ext1_wakeup_io()<\/span> function. Pass as arguments the bitmask of the GPIOs used for wake-up, and the mode\/logic for waking up.<\/p>\n\n\n\n You can use one of the following two logics:<\/p>\n\n\n\n If you\u2019re using an ESP32-S2, ESP32-S3, ESP32-C6 or ESP32-H2, these are the available modes:<\/p>\n\n\n\n Note<\/strong>: you can only use pins that are RTC GPIOs.<\/p>\n\n\n\n In the following example, we’ll use two pushbuttons to wake up the ESP32. The ESP32 will wake up when any of the pushbuttons are pressed.<\/p>\n\n\n\n To test this example, we’ll connect a pushbutton to GPIO27 and another to GPIO26. We’ll be using the ESP32 internal pull-down resistors. You can use the following diagram as a reference to wire your circuit.<\/p>\n\n\n And this is the code you should upload to your board.<\/p>\n\n\n View raw code<\/a><\/p>\n\n\n\n When you press any of the buttons, the ESP32 will wake-up and print which GPIO\/button was pressed.<\/p>\n\n\n Besides the ext0 <\/strong>and ext1 <\/strong>methods, there is another method that allows you to configure individual GPIOs to wake up the ESP32 on either HIGH or LOW signals. With this method, you can use any GPIO, whether it’s an RTC GPIO or a “regular” digital input.<\/p>\n\n\n\n 1) <\/strong>To use this method, first, you need to use the gpio_wakeup_enable()<\/span> function to define the GPIOs you want to use as a wake-up source and the corresponding level. The GPIO number must be in this format GPIO_NUM_X<\/span> (X is the number of the GPIO). The level can be one of the following options:<\/p>\n\n\n\n 2)<\/strong> You can call the gpio_wakeup_enable()<\/span> function several times to set up multiple GPIOs.<\/p>\n\n\n\n 3)<\/strong> After setting the GPIOs that will wake-up the ESP32, you must call the esp_sleep_enable_gpio_wakeup()<\/span> function to enable this wake-up source.<\/p>\n\n\n\n Then, you just need to call the esp_light_sleep_start()<\/span> function to put the ESP32 in light sleep state.<\/p>\n\n\n\n The following example works exactly like the previous one, but we use this new method. We use interrupts on the pushbuttons to determine which one was the cause of the wake-up.<\/p>\n\n\n View raw code<\/a><\/p>\n\n\n\n In this code, you start by defining the GPIOs connected to the pushbuttons in the following format:<\/p>\n\n\n\n We create a global variable to save the GPIO that caused the wake-up.<\/p>\n\n\n\n In the setup()<\/span>, use the gpio_wakeup_enable()<\/span> function to set the GPIOs as wake-up sources and the level.<\/p>\n\n\n\n Then, to enable the GPIOs as a wake-up source, call the esp_sleep_enable_gpio_wakeup()<\/span> function.<\/p>\n\n\n\n Still in the setup()<\/span>, we set the pushbuttons as interrupts so that they trigger a function when they’re pushed. This allows us to check which GPIO caused the wake-up.<\/p>\n\n\n\n Recommended reading<\/strong>: Interrupts with the ESP32 using a PIR Motion Sensor<\/a>.<\/p>\n\n\n\n The interrupt handler functions are defined before the setup()<\/span>, and update the wakeup_gpio<\/span> variable.<\/p>\n\n\n\n In the loop()<\/span>, like in previous examples, we update the counter<\/span> variable, light up the onboard LED, and put the board into light sleep mode.<\/p>\n\n\n\n After waking up from sleep, we print the GPIO that caused the wake-up.<\/p>\n\n\n\n It’s possible to wake up the ESP32 from light sleep when touching its touch pins\u2014basically when a touch sensor interrupt occurs. For that, use the touchSleepWakeUpEnable()<\/span> function that accepts as argument the touch pin and the threshold to wake up. For example:<\/p>\n\n\n\n The values read by a touch pin decrease when you touch it. The threshold value means that the ESP32 will wake up when the value read on the touch pin is below 40. You can adjust that value depending on the desired sensitivity.<\/p>\n\n\n\n Recommended reading:<\/strong> ESP32 Touch Pins with Arduino IDE<\/a>.<\/p>\n\n\n\n Important:<\/strong> however, if you\u2019re using an ESP32-S2 or ESP32-S3 model, things work a little differently. In that case, the lower the value, the more the sensitivity.<\/p>\n\n\n\n\n
\n
Prerequisites<\/h2>\n\n\n\n
\n
Introducing Light Sleep<\/h2>\n\n\n\n
![\"power](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2019\/02\/POWER-MODES.jpg?resize=667%2C174&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n![\"esp32](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2019\/02\/power-consumption-1.png?resize=857%2C344&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nSetting Up Light Sleep on the ESP32<\/h2>\n\n\n\n
esp_light_sleep_start();<\/code><\/pre>\n\n\n\nLight Sleep Wake-Up Sources<\/h2>\n\n\n\n
\n
\n
\n
\n
Disable Sleep Wake-Up Sources<\/h3>\n\n\n\n
\n\n\n\nLight Sleep with Timer Wake-Up<\/h2>\n\n\n\n
esp_sleep_enable_timer_wakeup(uint64_t time_in_us)<\/code><\/pre>\n\n\n\nESP32 Light Sleep with Timer Wake-Up Example<\/h3>\n\n\n\n
\/*********\n Rui Santos & Sara Santos - Random Nerd Tutorials\n Complete project details at https:\/\/RandomNerdTutorials.com\/esp32-light-sleep-arduino\/\n*********\/\n\nint counter = 0;\nconst int ledPin = 2; \/\/ GPIO pin for onboard LED\nuint64_t sleepTime = 10000000; \/\/ Sleep duration in microseconds (10 seconds)\n\nvoid setup() {\n Serial.begin(115200);\n pinMode(ledPin, OUTPUT);\n\n \/\/ Enable wake-up by timer\n esp_err_t result = esp_sleep_enable_timer_wakeup(sleepTime);\n\n if (result == ESP_OK) {\n Serial.println("Timer Wake-Up set successfully as wake-up source.");\n } else {\n Serial.println("Failed to set Timer Wake-Up as wake-up source.");\n }\n}\n\nvoid loop() {\n Serial.printf("Counter: %d\\n", counter);\n counter++;\n\n digitalWrite(ledPin, HIGH); \/\/ LED on to indicate wake-up\n delay(2000);\n digitalWrite(ledPin, LOW); \/\/ Turn off LED before going to sleep\n\n Serial.println("Going into light sleep mode");\n delay(500);\n esp_light_sleep_start(); \/\/ Enter light sleep\n Serial.println("Returning from light sleep");\n}\n<\/code><\/pre>\n\tHow Does the Code Work?<\/h4>\n\n\n\n
esp_err_t result = esp_sleep_enable_timer_wakeup(sleepTime);<\/code><\/pre>\n\n\n\nif (result == ESP_OK) {\n Serial.println(\"Timer Wake-Up set successfully as wake-up source.\");\n} else {\n Serial.println(\"Failed to set Timer Wake-Up as wake-up source.\");\n}<\/code><\/pre>\n\n\n\ncounter++;<\/code><\/pre>\n\n\n\ndigitalWrite(ledPin, HIGH); \/\/ LED on to indicate wake-up\ndelay(2000);\n digitalWrite(ledPin, LOW); \/\/ Turn off LED before going to sleep<\/code><\/pre>\n\n\n\nesp_light_sleep_start(); \/\/ Enter light sleep<\/code><\/pre>\n\n\n\nSerial.println(\"Returning from light sleep\");<\/code><\/pre>\n\n\n\n![\"ESP32](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2024\/10\/ESP32-Light-Sleep-Timer-Wake-Up-Demonstration-Serial-Monitor.png?resize=749%2C290&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n
\n\n\n\nLight Sleep with External Wake-Up<\/h2>\n\n\n\n
ext0 External Wake-Up<\/h3>\n\n\n\n
esp_sleep_enable_ext0_wakeup(GPIO_NUM_27, level);<\/code><\/pre>\n\n\n\n\n
Light Sleep with External Wake-Up Example (ext0)<\/h4>\n\n\n\n
![\"ESP32](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2024\/11\/ESP32-pushbutton-internal-pull-down-resistor-1.png?resize=847%2C832&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n\/*********\n Rui Santos & Sara Santos - Random Nerd Tutorials\n Complete project details at https:\/\/RandomNerdTutorials.com\/esp32-light-sleep-arduino\/\n*********\/\n\nint counter = 0;\nconst int ledPin = 2; \/\/ GPIO pin for onboard LED\n#define buttonPin GPIO_NUM_27 \/\/ Connect a pushbutton to GPIO 27\n\nvoid setup() {\n Serial.begin(115200);\n pinMode(ledPin, OUTPUT);\n pinMode(buttonPin, INPUT_PULLDOWN); \/\/ pull-down resistor\n\n \/\/ Enable wake-up by EXT0 using the button on GPIO 27\n esp_err_t result = esp_sleep_enable_ext0_wakeup(buttonPin, 1); \/\/ 1 = wake up on HIGH signal\n\n if (result == ESP_OK) {\n Serial.println("EXT0 Wake-Up set successfully as wake-up source.");\n } else {\n Serial.println("Failed to set EXT0 Wake-Up as wake-up source.");\n }\n}\n\nvoid loop() {\n Serial.printf("Counter: %d\\n", counter);\n counter++;\n\n digitalWrite(ledPin, HIGH); \/\/ LED on to indicate wake-up\n delay(5000);\n digitalWrite(ledPin, LOW); \/\/ Turn off LED before going to sleep\n\n Serial.println("Going into light sleep mode");\n delay(500);\n esp_light_sleep_start(); \/\/ Enter light sleep\n Serial.println("Returning from light sleep");\n}<\/code><\/pre>\n\tHow does the code work?<\/h4>\n\n\n\n
#define buttonPin GPIO_NUM_27 \/\/ GPIO pin for pushbutton<\/code><\/pre>\n\n\n\npinMode(buttonPin, INPUT_PULLDOWN); \/\/ pull-down resistor<\/code><\/pre>\n\n\n\n\/\/ Enable wake-up by EXT0 using the button on GPIO 27\nesp_err_t result = esp_sleep_enable_ext0_wakeup(buttonPin, 1); \/\/ 1 = wake up on HIGH signal<\/code><\/pre>\n\n\n\nesp_light_sleep_start(); \/\/ Enter light sleep<\/code><\/pre>\n\n\n\nTesting the Code<\/h4>\n\n\n\n
![\"ESP32](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2024\/11\/ESP32-light-sleep-ext0-demonstration.png?resize=666%2C324&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\next1 External Wake-Up<\/h3>\n\n\n\n
\n
\n
Light Sleep with External Wake-Up () Example (ext1)<\/h4>\n\n\n\n
![\"ESP32](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2024\/11\/ESP32-with-two-pushbuttons-internal-pull-down-resistors.png?resize=808%2C747&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n\/*********\n Rui Santos & Sara Santos - Random Nerd Tutorials\n Complete project details at https:\/\/RandomNerdTutorials.com\/esp32-light-sleep-arduino\/\n*********\/\n\n#include "esp_sleep.h"\n#include "driver\/rtc_io.h"\n\nint counter = 0;\nconst int ledPin = 2; \/\/ GPIO pin for onboard LED\nconst gpio_num_t buttonPin1 = GPIO_NUM_26; \/\/ RTC IO for pushbutton 1\nconst gpio_num_t buttonPin2 = GPIO_NUM_27; \/\/ RTC IO for pushbutton 2\n#define BUTTON_PIN_BITMASK(GPIO) (1ULL << GPIO) \/\/ Macro for individual GPIO bitmask\n\n\/\/ Create a bitmask for GPIO 26 and GPIO 27\nuint64_t bitmask = BUTTON_PIN_BITMASK(buttonPin1) | BUTTON_PIN_BITMASK(buttonPin2);\n\n\/\/ Method to print the GPIO that triggered the wakeup\nvoid print_GPIO_wake_up(){\n int GPIO_reason = esp_sleep_get_ext1_wakeup_status();\n Serial.print("GPIO that triggered the wake up: GPIO ");\n Serial.println((log(GPIO_reason))\/log(2), 0);\n}\n\nvoid setup() {\n Serial.begin(115200);\n pinMode(ledPin, OUTPUT);\n pinMode(buttonPin1, INPUT_PULLDOWN); \/\/ pull-down resistor\n pinMode(buttonPin2, INPUT_PULLDOWN); \/\/ pull-down resistor\n\n \/\/ Configure GPIO 26 and GPIO 27 as RTC IOs for EXT1 wake-up\n rtc_gpio_deinit(buttonPin1);\n rtc_gpio_deinit(buttonPin2);\n\n \/\/ Enable EXT1 wake-up source\n esp_err_t result = esp_sleep_enable_ext1_wakeup(bitmask, ESP_EXT1_WAKEUP_ANY_HIGH);\n\n if (result == ESP_OK) {\n Serial.println("EXT1 Wake-Up set successfully.");\n } else {\n Serial.println("Failed to set EXT1 Wake-Up as wake-up source.");\n }\n}\n\nvoid loop() {\n Serial.printf("Counter: %d\\n", counter);\n counter++;\n\n digitalWrite(ledPin, HIGH); \/\/ LED on to indicate wake-up\n delay(2000);\n digitalWrite(ledPin, LOW); \/\/ Turn off LED before going to sleep\n\n Serial.println("Going into light sleep mode");\n delay(500);\n esp_light_sleep_start(); \/\/ Enter light sleep\n\n \/\/ After wake-up, disable the hold function on the RTC GPIOs\n rtc_gpio_hold_dis(buttonPin1);\n rtc_gpio_hold_dis(buttonPin2);\n\n Serial.println("----------------------");\n Serial.println("Returning from light sleep");\n \/\/ Print the GPIO (button) that caused the wake-up\n print_GPIO_wake_up();\n}<\/code><\/pre>\n\t![\"ESP32](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2024\/11\/ESP32-light-sleep-ext1-multiple-gpios.png?resize=768%2C366&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nGPIO External Wake-Up<\/h3>\n\n\n\n
\n
Light Sleep with GPIO External Wake-Up Example<\/h4>\n\n\n\n
\/*********\n Rui Santos & Sara Santos - Random Nerd Tutorials\n Complete project details at https:\/\/RandomNerdTutorials.com\/esp32-light-sleep-arduino\/\n*********\/\n\n#include "esp_sleep.h"\n#include "driver\/gpio.h"\n\nint counter = 0;\nconst int ledPin = 2; \/\/ GPIO pin for onboard LED\nconst gpio_num_t buttonPin1 = GPIO_NUM_26; \/\/ GPIO for pushbutton 1\nconst gpio_num_t buttonPin2 = GPIO_NUM_27; \/\/ GPIO for pushbutton 2\n\nint wakeup_gpio; \/\/ Variable to store the GPIO that caused wake-up\n\n\/\/ ISR for buttonPin1\nvoid IRAM_ATTR handleInterrupt1() {\n wakeup_gpio = buttonPin1;\n}\n\n\/\/ ISR for buttonPin2\nvoid IRAM_ATTR handleInterrupt2() {\n wakeup_gpio = buttonPin2;\n}\n\nvoid setup() {\n Serial.begin(115200);\n pinMode(ledPin, OUTPUT);\n pinMode(buttonPin1, INPUT_PULLDOWN); \/\/ pull-down resistor\n pinMode(buttonPin2, INPUT_PULLDOWN); \/\/ pull-down resistor\n\n \/\/ Configure GPIOs as wake-up source\n gpio_wakeup_enable(buttonPin1, GPIO_INTR_HIGH_LEVEL); \/\/ Trigger wake-up on high level\n gpio_wakeup_enable(buttonPin2, GPIO_INTR_HIGH_LEVEL); \/\/ Trigger wake-up on high level\n\n \/\/ Enable GPIO wake-up source\n esp_err_t result = esp_sleep_enable_gpio_wakeup();\n\n if (result == ESP_OK) {\n Serial.println("GPIO Wake-Up set successfully.");\n } else {\n Serial.println("Failed to set GPIO Wake-Up as wake-up source.");\n }\n\n \/\/ Attach interrupts to GPIO pins\n attachInterrupt(digitalPinToInterrupt(buttonPin1), handleInterrupt1, RISING);\n attachInterrupt(digitalPinToInterrupt(buttonPin2), handleInterrupt2, RISING);\n}\n\nvoid loop() {\n Serial.printf("Counter: %d\\n", counter);\n counter++;\n\n digitalWrite(ledPin, HIGH); \/\/ LED on to indicate wake-up\n delay(5000);\n digitalWrite(ledPin, LOW); \/\/ Turn off LED before going to sleep\n\n Serial.println("Going into light sleep mode");\n delay(500);\n esp_light_sleep_start(); \/\/ Enter light sleep\n\n Serial.println("----------------------");\n Serial.println("Returning from light sleep");\n\n \/\/ Print the GPIO that caused the wake-up\n Serial.printf("Wake-up caused by GPIO %d\\n", wakeup_gpio);\n}<\/code><\/pre>\n\tconst gpio_num_t buttonPin1 = GPIO_NUM_26; \/\/ GPIO for pushbutton 1\nconst gpio_num_t buttonPin2 = GPIO_NUM_27; \/\/ GPIO for pushbutton 2<\/code><\/pre>\n\n\n\nint wakeup_gpio; \/\/ Variable to store the GPIO that caused wake-up<\/code><\/pre>\n\n\n\n\/\/ Configure GPIOs as wake-up source\ngpio_wakeup_enable(buttonPin1, GPIO_INTR_HIGH_LEVEL); \/\/ Trigger wake-up on high level\ngpio_wakeup_enable(buttonPin2, GPIO_INTR_HIGH_LEVEL); \/\/ Trigger wake-up on high level<\/code><\/pre>\n\n\n\n\/\/ Enable GPIO wake-up source\nesp_err_t result = esp_sleep_enable_gpio_wakeup();<\/code><\/pre>\n\n\n\n\/\/ Attach interrupts to GPIO pins\nattachInterrupt(digitalPinToInterrupt(buttonPin1), handleInterrupt1, RISING);\nattachInterrupt(digitalPinToInterrupt(buttonPin2), handleInterrupt2, RISING);<\/code><\/pre>\n\n\n\n\/\/ISR for buttonPin1\nvoid IRAM_ATTR handleInterrupt1() {\n wakeup_gpio = buttonPin1;\n}\n\n\/\/ISR for buttonPin2\nvoid IRAM_ATTR handleInterrupt2() {\n wakeup_gpio = buttonPin2;\n}<\/code><\/pre>\n\n\n\nSerial.printf(\"Counter: %d\\n\", counter);\ncounter++;\n\ndigitalWrite(ledPin, HIGH); \/\/ LED on to indicate wake-up\ndelay(5000);\ndigitalWrite(ledPin, LOW); \/\/ Turn off LED before going to sleep\n\nSerial.println(\"Going into light sleep mode\");\ndelay(500);\nesp_light_sleep_start(); \/\/ Enter light sleep<\/code><\/pre>\n\n\n\nSerial.println(\"----------------------\");\nSerial.println(\"Returning from light sleep\");\n\n\/\/ Print the GPIO that caused the wake-up\nSerial.printf(\"Wake-up caused by GPIO %d\\n\", wakeup_gpio);<\/code><\/pre>\n\n\n\n
\n\n\n\nLight Sleep with Touch Wake-Up<\/h2>\n\n\n\n
touchSleepWakeUpEnable(T3, THRESHOLD);<\/code><\/pre>\n\n\n\n