LED Brightness Control Module

LED Brightness

This module allows you to control the brightness of devices such as LEDs. You can enter the pin number to which your device is connected and vary the brightness.

If your device is connected to a digital pin, you can turn it ON or OFF by pressing the power button in the center of the screen.

If your device is connected to a PWM pin, you can vary its brightness by sliding the green bar in the clockwise direction.

Available in


The LED Brightness Control is the first module of the Dabble App. 

This module allows you to control the output of the digital pins in two ways:

  1. If the pin is a digital pin with no PWM support, then you can control the HIGH and LOW state of the pin by clicking on the ON/OFF icon present in the center of the module.

    Dabble LED Brightness Value 0
    LED Brightness module controlling digital pin 13. The current state of LED is set to OFF.

    Dabble LED Brightness Value 100
    LED Brightness module controlling Digital Pin13. The current state of LED is set to ON.

  2. If the digital pin is a PWM pin then you can also vary PWM of that pin in order to get different output voltage at that pin. Potentiometer type knob as seen in the image is used for controlling PWM. Knob range is from 0 to 100 and it is mapped to PWM values. The module is made for activities like controlling LEDs. 

How to change the Pin?

To change the pin, you can click on the button showing the Pin (In the above image it is Pin: 13 button).

Dabble App Choose Pin

You can choose the following pins for the corresponding boards:

  1. evive:
    1.   PWM pins: digital pins 2-13
    2.   Digital pins with no brightness control: digital pins 21-26
  2. Arduino Uno:
    1.   PWM pins: digital pins 3,5,6,9,10 and 11
    2.   Digital pins with no brightness control: digital pins 2,4,7,8,12 and 13
  3. Arduino Mega:
    1.   PWM pins: digital pins 2-13 and 44-46
    2.   Digital pins with no brightness control: digital pins 14-43 and 47-53

Arduino IDE Functions


To include the LED Control module in the Arduino program, you have to include the following header:



After defining the above mention headers, you have to include the dabble library:

#include <Dabble.h>

You can download the zip of Arduino Library for

  1. evive, Uno, Mega, and Nano – Dabble-Arduino 
  2. ESP32 – Dabble-ESP32

depending on the board you are using.

Enabling Bluetooth Communication

To enable Bluetooth communication, you have to initialize serial communication using the following code:

  1. For evive and Arduino Mega, Uno and Nano

    Here Baud_Rate is the baud rate set for the Bluetooth module. With evive, you normally get 115200 baud rate modules.

  2. For ESP32

    In place of Bluetooth_Name  enter name that you want to keep for Bluetooth of ESP32. The default name given in the library is “MyEsp32”. 

Refreshing the data

To refresh the data that the device has got from the mobile app, you have to use the following line of code:


This function also changes the state and the brightness of the LED automatically and you don’t have to do anything.


If you want to get the pin number, its state and brightness value of the LED from the module, then these are the functions using which you can do that:

  1. LedControl.getpinNumber(): This function returns the pin selected for LED Brightness control in the mobile app. The function returns int data type.
  2. LedControl.getpinState(): The function returns the state of the pin set by the user in the mobile app. This function returns the following output:
    1.   1 if the state is set to ON
    2.   0 if the state is set to OFF
  3. LedControl.readBrightness(): This function returns the brightness value set by the user in the mobile app. It returns int data type with a value ranging between 0 and 100.

PictoBlox (Scratch) Blocks

There is a stacked block named as “ enable LED control” available for this module. Its function is to enable the LED Brightness Control feature of Dabble.

enable LED control

evive Notes Icon
Note: When you are using this module with Arduino Uno, Mega, and Nano,  you have to set the Bluetooth baud rate to the baud rate of the Bluetooth module to have proper communication between the board and the module. To set the baud rate you have to use set bluetooth baud rate to () block.

set bluetooth baud rate to


Click here to view Arduino IDE Example for LED Brightness Control Module

Here in this example, we are controlling the LED brightness and also displaying the pin number, state, and brightness of the LED on the serial monitor. Either copy the codes are given below as per your selected board or you can also navigate to “Files>>Examples>>Dabble>>” and select Led Brightness Control example as per your board.

eviveYou can enter pin value as 13 in the Dabble app since there is an in-built led present on evive at pin 13.

Arduino Mega, Uno and NanoTo work with onboard led enter pin 13 in the Dabble app.


In some ESP32 dev module onboard led comes on gpio pin 2, if your module has onboard led then you can use its corresponding pin to check the functionality of this module or else connect led to any pin and control it through the app.


Click here to view PictoBlox (Scratch) Example for LED Brightness Control Module

To access the LED Brightness Control feature for the very first time, you have to upload the following script.

  1.  Stage Mode
    Enable LED control example stage mode
    evive Notes Icon
    Note: When working with evive or any of your Arduino board on PictoBlox for the very first time, or if you’ve previously uploaded another code to your board, you must upload the firmware in order to work in stage mode. You can find the procedure for the same here.
  2. Upload Mode

Enable LED control example

Depending upon your board type choose the corresponding head block. As seen in the example above with evive “when evive starts up” head block is chosen. Similarly, for the Arduino UNO board, you can choose “when Uno starts up” block. Currently, PictoBlox supports evive and Arduino Uno, Nano and Mega boards. Support for the ESP32 board will be added soon. 


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