Communication, Programming



Getting Started with the ESP32 on Arduino IDE

    Written by Mohammadreza Akbari


Overview

In this tutorial, you’ll get to know the ESP32 Wi–Fi and Bluetooth
 module and how to set it up. 
What You Will Learn

    Introduction to the ESP32 and its applications
    Installing the ESP32 on Arduino IDE


What is ESP32?

One of the most popular and practical modules of the past few years is the
 ESP8266 Wi–Fi module. There are various versions of this module available
 on the market.  The ESP32 module is an upgraded version of the ESP8266. In
 addition to the Wi-Fi module, this module also has a Bluetooth module of
 version 4. Having dual-core CPU working in 80 to 240 MHz frequency, and
 containing two Wi–Fi and Bluetooth modules and various input and output
 pins, the ESP32 is an ideal choice to use in internet of things projects.
 (IOT). 




The ESP32 Module Features




Working Voltage
2.2 to 3.6 volts
Average Current
Around 80 mA
Maximum Current
500 mA
Input/Output Pins
32(The ESP32 chip has 48 I/O pin,s. But the module has
 only 28 accessible pins.)
ADC(Analog to Digital Converter)
18 channels of 12 bits
DAC(Digital to Analog Converter)
2 channels of 8 bits
UART(Serial Communication)
3
PWM
32
SPI Interface
4
I2C Interface
2
I2S Interface (to connect audio devices)
2
Capacitance TouchPads Pins
10
Memory Card Interface
1
CAN Interface
1
Temperature Sensor
1


Note
You may not have access to some ESP32 chip pins in some modules.


The ESP32 Module Pinout




Although the ESP32 has fewer pins than commonly used processors, you won’t
 face any problem with multiplexing multiple functions on a pin. 


Warning
The voltage level of the ESP32 pins is 3.3 volts. If you want to connect
 ESP32 to other devices that operate at 5–volts voltage, you should use a
 level shifter to convert the voltage level.


Supply Pins:


The module has two 5V and 3.3V power supply pins. You can use these two pins
 to supply other devices and modules. 



GND Pin:



The module has 3 pins for its ground. 


Enable Pin (EN):


This pin is used to enable and disable the module. It should be HIGH to
 enable the module and must be LOW to disable it. 


Input/Output Pins (GPIO):


You can use the 32 GPIO pins to communicate with the LEDs, switches, and
 other input/output devices. 

You can pull-up or pull-down these pins internally. 


Note
The GPIO6 to GPIO11 pins which are SCK / CLK, SDO / SD0, SDI / SD1, SHD /
 SD2, SWP / SD3, and SCS / CMD pins, are used for SPI communication of the
 internal flash memory of the module and we do not recommend you to use
 them.  



ADC:


You can use the 16 ADC pins on this module to convert analog voltages
 (output of some sensors) to digital. Some of these converters are connected
 to the internal amplifier and are able to measure small voltages with high
 precision. 



DAC:


The ESP32 module has two digital to analog converters with 8 bits accuracy.
 



Touchpads:


There are 10 pins on the ESP32 module that are sensitive to capacitor
 changes. You can connect these pins to some pads (the pads on the PCB) and
 use them as touch switches. 




SPI:


There are two SPI interfaces on this module that you can use to connect the
 display, the SD / microSD memory card module, external flash memory, and
 more. 



I2C:


SDA and SCL pins are used for I2C communication.



Serial Communication (UART):


There are two UART serial interfaces on this module. Using these pins, you
 can transfer information up to 5Mbps, between two devices. UART0 has also
 CTS and RTS bases. 



PWM:


Almost all of the ESP32 input/output pins can be used for PWM (Pulse Width
 Modulation). Using these pins you can control the motors, LEDs light and
 color and so on. 


The ESP32 Module Modes


The ESP32 chip has 5 modes: 


Active mode:


In this case, all parts of the Wi-Fi and Bluetooth transmitter and receiver
 are active. In this case, the current consumption is between 80 and 260 mA.
 


Modem-sleep mode:


The processor is still active, but the Wi–Fi and Bluetooth are disabled.
 The current consumption is between 3 and 20 mA, in this case. 


Light-sleep mode:


The main processor stops working, but the RTC unit and the ULP processor
 unit are still active. The current consumption is about 0.8 mA. 


Deep-sleep mode:


Only the RTC unit is active. In this case, the data of Wi-Fi and Bluetooth
 communications are stored in the RTC’s memory. The current consumption is
 between 10 and 150 μA in this mode. 


Hibernation mode:


All units are disabled, except for an RTC timer for the clock and some I / O
 pins connected to the RTC. The RTC timer or the connected pins can wake the
 chip up from this state. The current consumption is about 2.5 μA in this
 case. 

For more information, you can check the module datasheet. 

ESP32 chip and Module Datasheet


The datasheet of ESP32 module and its chipset can be downloaded from the
 following links. 


https://www.espressif.com/sites/default/files/docum
entation/esp32_datasheet_en.pdf 
https://espressif.com/sites/default/files/documentation/esp32-wroom
-32_datasheet_en.pdf 



ESP32 VS. ESP8266

Various types of ESP32 and ESP8266 modules are available on the market. In
 this part, the ESP8266 NodeMcu and ESP32 DEV modules are compared together:
 



ESP8266 NodeMcu
ESP32 DEV Module
Power
3.3V
3.3V
CPU
Tensilica L106 32-bit
Xtensa® Dual-Core 32-bit LX6
Bluetooth
Do not have
Compliant with Bluetooth v4.2 BR/EDR and BLE
 specification
GPIO
17
32
Flash size
Up to 16MB
Up to 16MB
ADC
10 bit
12 bit
DAC
Do not have
2 * 8bit
UART
2
2


Usually, ESP32 modules are more expensive than ESP8266. So, if you do not
 need Bluetooth, digital converter, many  I / O pins, and …, you can save
 your money by purchasing ESP8266 modules.


Required Materials


Hardware Components
ESp32 	× 	1 	
Software Apps
Arduino IDE 	


Installing the ESP32 on Arduino IDE

The installation process of ESP32 is almost the same as the ESP8266
 installation. To install ESP32 on the Arduino IDE, do the following steps:

Note
You need Arduino IDE version 1.8.5 or higher to install the ESP32 on it. 



First Step: Downloading the required files from the GitHub


Download the ESP32 Arduino Core from its GitHub account. You can use the
 direct download link as well. 

https://github.com/espressif/arduino-esp32/archive/master.zip


Second Step: Move the file to Arduino sketchbook location


The Arduino sketchbook is located in My Documents by default. To find the
 exact path of your sketchbook, check the preferences from the File menu. 


Create a new folder named hardware next to the Arduino folder in your
 sketchbook location. 


Create a folder named espressif inside the hardware folder, then create
 another folder named esp32 inside the espressif folder. Finally, the path
 you created should be like the following picture: 


Extract the file you downloaded in the previous step and move it to this
 address. 



Third Step: Run the get.exe


To install ESP32 on the Arduino software, you need to install the Xtensa GNU
 compiler collection on your system. Go to esp32> tools and run the get.exe
 file. 



After running the get.exe, the required files are automatically downloaded
 and transferred to the tools folder. This step may take some time.


After the installation is completed, new files must be added to the tools
 folder. 



Uploading the Codes on ESP32 Using Arduino IDE


Uploading the codes on the ESP32 module is similar to other Arduino boards.
 You can use Arduino built–in examples, like Blink, to test it. 

Tip
If you did not install CP2102 driver in your computer before, you should
 download it from here, then install it.

To upload your code, select the board type from the Tools menu. Then select
 the port connected to your board and click on the upload. 


/*F************************************************
***************************
* 
****************************************************
************************/
void 
setup() 
{
	pinMode( 2, OUTPUT );
}
/*F*************************************************
**************************
* 
****************************************************
************************/
void loop() 
{
	digitalWrite( 2, HIGH);           // TURN LED ON (HIGH IS VOLTAGE LEVEL)
	delay( 1000 );                                      // WAIT FOR A SECOND
	digitalWrite( 2, LOW );            // TURN LED OFF BY MAKING VOLTAGE LOW
	delay( 1000 );                                      // WAIT FOR A SECOND
}


Troubleshooting

If you are faced with the following error, do not worry. This problem
 usually occurs while programming the ESP32. Do the following steps to solve
 the problem: 


Make sure the upload speed is set correctly. Usually, this speed should be
 115200. 



2.Press and hold the Boot button on your board. 

       3.Click on the Upload option. 

       4.When you see the message Writing at 0x00001000 … (100%), 
		remove your finger from the Boot button. 


       5.You must see the Done uploading message when the uploading is
 finished.



What’s Next?


Create an HTTP page and control an LED through a webpage. 
Control the LED using Bluetooth communication. (You can use Bluetooth
 terminals to do this.) 

PrevPreviousColor Recognition w/ TCS230 Sensor and Arduino [Calibration Code
 included]