Acoptex.com

1

member

Basics: Project 072u

Project name: ESP32 Development board with DC Motor and L298N H-Bridge motor driver module

Tags: ESP32 Dev Module, ESP32 development board, ESP32 Development board with WiFi and Bluetooth, ESP32-DevKitC V4 development board, ESP-WROOM-32 module with ESP32‑D0WDQ6 chip, Espressif Systems, ESP32-based development board, ESP32 modules, ESP32-WROOM-32, ESP32-WROOM-32U, ESP32-WROOM-32D, ESP32-SOLO-1, USB-UART bridge, IOT, ESP-WROOM-32 Dev Module, ESP32 DEVKITV1, Installing the ESP32 Board in Arduino IDE, Uploading sketch, DC Motor, L298N Motor Driver, L298N H-Bridge motor driver module

Attachments: WithoutSpeedcontrolsketch1,

WithSpeedcontrolsketch2,

In this project, you need these parts :

1. ESP32 development board with WiFi and Bluetooth and USB A / micro USB B cable 1 pc

2.Arduino IDE ( you can download it from here  )

3.Jumper cables F-F

4. L298N H-Bridge motor driver module (as you see they can be a little bit different but have the same working principle) 1pc

5. DC motor 6V 1 pc

6. External motor power supply 1 pc

7. External L298N IC logics power supply (optional, depending on external motor power supply) 1 pc

8.100nF ceramic capacitors 2 pcs (optional)

9. SPDT slide switch 1 pc (optional)

General

We will learn how to control the direction and speed of a DC motor using an ESP32 development board and the L298N H-Bridge motor driver module. 

There are a lot of different development boards made. You can find more information about them here. 

Understanding the DC motor

You can read more about it here.

Understanding the L298N H-Bridge motor driver module

You can read more about it here.

Understanding the ESP32 Development board with WiFi and Bluetooth

We will discuss here an Espressif Systems products. Our development board is using ESP-WROOM-32 module from Espressif Systems.

Espressif offers a wide range of fully-certified Wi-Fi & BT modules powered by their own advanced SoCs.

1. Dual-core Modules with Wi-Fi & Dual-mode Bluetooth

Features

• Two independently-controlled CPU cores with adjustable clock frequency, ranging from 80 MHz to 240 MHz
• +19.5 dBm output at the antenna ensures a good physical range
• Classic Bluetooth for legacy connections, also supporting L2CAP, SDP, GAP, SMP, AVDTP, AVCTP, A2DP (SNK) and AVRCP (CT)
• Support for Bluetooth Low Energy (BLE) profiles including L2CAP, GAP, GATT, SMP, and GATT-based profiles like BluFi, SPP-like, etc
• Bluetooth Low Energy (BLE) connects to smart phones, broadcasting low-energy beacons for easy detection
• Sleep current is less than 5 μA, making it suitable for battery-powered and wearable-electronics applications
• Integrates 4 MB flash
• Peripherals include capacitive touch sensors, Hall sensor, low-noise sense amplifiers, SD card interface, Ethernet, high-speed SPI, UART, I2S and I2C
• Fully certified with integrated antenna and software stacks

2. Single-core Modules with Wi-Fi & Dual-mode Bluetooth

Features

• High-performance 160 MHz single-core CPU
• +19.5 dBm output at the antenna ensures a good physical range
• Classic Bluetooth for legacy connections, also supporting L2CAP, SDP, GAP, SMP, AVDTP, AVCTP, A2DP (SNK) and AVRCP (CT)
• Support for Bluetooth Low Energy (BLE) profiles including L2CAP, GAP, GATT, SMP, and GATT-based profiles like BluFi, SPP-like, etc
• Bluetooth Low Energy (BLE) connects to smart phones, broadcasting low-energy beacons for easy detection
• Sleep current is less than 5 μA, making it suitable for battery-powered and wearable-electronics applications
• Peripherals include capacitive touch sensors, Hall sensor, low-noise sense amplifiers, SD card interface, Ethernet, high-speed SPI, UART, I2S and I2C
• Fully certified with integrated antenna and software stacks

3. Single-core Modules with 802.11b/g/n 2.4 GHz Wi-Fi

Features

• High-performance 160 MHz single-core CPU
• +19.5 dBm output at the antenna ensures a good physical range
• Sleep current is less than 20 μA, making it suitable for battery-powered and wearable-electronics applications
• Peripherals include UART, GPIO, I2C, I2S, SDIO, PWM, ADC and SPI
• Fully certified with integrated antenna and software stacks

There are different development Boards made by Espressif Systems and other manufacturers. We will publish some information about Espressif Systems boards but you can also find out more information about other development boards here.

1. 2.4 GHz Wi-Fi & BT/BLE Development Boards

Features

• PC connectivity: USB
• Power supply options: USB (by default), or 5V/GND header pins, or 3V3/GND header pins
• SDK: ESP-IDF source code and example applications

2. 2.4 GHz Wi-Fi Development Boards

Features

• PC connectivity: USB
• SDK: ESP8266 SDK source code and example applications

3. 2.4 GHz Wi-Fi + BT/BLE + Sensor Development Boards

Features

• PC connectivity: USB
• SDK: ESP-IOT-SOLUTION source code and example applications

You can find more information (datasheets, schematics, pins descriptions, functional desgn descriptions) about each board by pressing Getting started link close to each board here.

ESP32 chip

ESP32 is a series of low cost, low power system on a chip microcontrollers with integrated Wi-Fi and dual-mode Bluetooth. The ESP32 series employs a Tensilica Xtensa LX6 microprocessor in both dual-core and single-core variations and includes in-built antenna switches, RF balun, power amplifier, low-noise receive amplifier, filters, and power management modules. ESP32 is created and developed by Espressif Systems, a Shanghai-based Chinese company, and is manufactured by TSMC using their 40 nm process. It is a successor to the ESP8266 microcontroller.

ESP32 can perform as a complete standalone system or as a slave device to a host MCU, reducing communication stack overhead on the main application processor. ESP32 can interface with other systems to provide Wi-Fi and Bluetooth functionality through its SPI / SDIO or I2C / UART interfaces.

ESP32 is highly-integrated with in-built antenna switches, RF balun, power amplifier, low-noise receive amplifier, filters, and power management modules. ESP32 adds priceless functionality and versatility to your applications with minimal Printed Circuit Board (PCB) requirements.

ESP32 is capable of functioning reliably in industrial environments, with an operating temperature ranging from –40°C to +125°C. Powered by advanced calibration circuitries, ESP32 can dynamically remove external circuit imperfections and adapt to changes in external conditions.

Engineered for mobile devices, wearable electronics and IoT applications, ESP32 achieves ultra-low power consumption with a combination of several types of proprietary software. ESP32 also includes state-of-the-art features, such as fine-grained clock gating, various power modes and dynamic power scaling.

Functional Block Diagram:

Features of the ESP32 include the following:

Processors:

• CPU: Xtensa dual-core (or single-core) 32-bit LX6 microprocessor, operating at 160 or 240 MHz and performing at up to 600 DMIPS
• Ultra low power (ULP) co-processor
• Memory: 520 KiB SRAM

Wireless connectivity:

• Wi-Fi: 802.11 b/g/n
• Bluetooth: v4.2 BR/EDR and BLE

Peripheral interfaces:

• 12-bit SAR ADC up to 18 channels
• 2 × 8-bit DACs
• 10 × touch sensors (capacitive sensing GPIOs)
• Temperature sensor
• 4 × SPI
• 2 × I²S interfaces
• 2 × I²C interfaces
• 3 × UART
• SD/SDIO/CE-ATA/MMC/eMMC host controller
• SDIO/SPI slave controller
• Ethernet MAC interface with dedicated DMA and IEEE 1588 Precision Time Protocol support
• CAN bus 2.0
• Infrared remote controller (TX/RX, up to 8 channels)
• Motor PWM
• LED PWM (up to 16 channels)
• Hall effect sensor
• Ultra low power analog pre-amplifier

Security:

• IEEE 802.11 standard security features all supported, including WFA, WPA/WPA2 and WAPI
• Secure boot
• Flash encryption
• 1024-bit OTP, up to 768-bit for customers
• Cryptographic hardware acceleration: AES, SHA-2, RSA, elliptic curve cryptography (ECC), random number generator (RNG)

Power management:

• Internal low-dropout regulator
• Individual power domain for RTC
• 5uA deep sleep current
• Wake up from GPIO interrupt, timer, ADC measurements, capacitive touch sensor interrupt

You can find ESP32 chip datasheet here, hardware design here, technical reference manual here.

Signals and connections of the L298N H-Bridge motor driver module

You can find read more information here.

Signals and connections of the ESP32 Development board with WiFi and Bluetooth

You can find more information (datasheets, schematics, pins descriptions, functional desgn descriptions) about each board (made by Espresiff Systems) by pressing Getting started link close to each board here.

Let's check our development board - ESP32 DEVKITV1 with ESP-WROOM-32 module from Espressif Systems:

Pinout diagram for the ESP Wroom 32 breakout:

ESP32-WROOM-32 - ESP32-WROOM-32 module soldered to the development board. Optionally ESP32-WROOM-32D, ESP32-WROOM-32U or ESP32-SOLO-1 module may be soldered instead of the ESP32-WROOM-32.

USB-UART Bridge - A single chip USB-UART bridge provides up to 3 Mbps transfers rates.

BOOT button - Download button: holding down the Boot button and pressing the EN button initiates the firmware download mode. Then user can download firmware through the serial port.

EN button - Reset button: pressing this button resets the system.

Micro USB Port - USB interface. It functions as the power supply for the board and the communication interface between PC and the ESP module.

TX0, TX2 - transmit pin. GPIO pin

RX0, RX2  - receive pin.  GPIO pin

3V3 (or 3V or 3.3V) - power supply pin (3-3.6V). 

GND - ground pin.

EN - Chip enable. Keep it on high (3.3V) for normal operation.

Vin - External power supply 5VDC.

Wiring

1. One DC motor without speed control. 

2. One DC motor with speed control. 

Step by Step instruction

The ESP32 is currently being integrated with the Arduino IDE like it was done for the ESP8266. There’s an add-on for the Arduino IDE that allows you to program the ESP32 using the Arduino IDE and its programming language.

1. Download and install the latest Arduino IDE Windows Installer from arduino.cc
2. Download and install Git and Git GUI from git-scm.com
3. Search for Git GUI, right-click the icon and select “Run as administrator“
4. 
5. Select the Clone Existing Repository option.
6. 
7. Select source and destination. Source Location: https://github.com/espressif/arduino-esp32.git
8. Target Directory:C:/Users/[YOUR_USER_NAME]/Documents/Arduino/hardware/espressif/esp32
9. Do not create the espressif/esp32 folders, because they will be created automatically.
10. 
11. Click Clone to start cloning the repository.Wait a few seconds while the repository is being cloned.
12. 
13. 
14. Open the folder: C:/Users/[YOUR_USER_NAME]/Documents/Arduino/hardware/espressif/esp32/tools
15. Right-click the get.exe file and select “Run as administrator“.
16. 
17. You will see that necessary files will be downloaded and upzipped. It will take some time.
18. 
19. When get.exe finishes, you should see the following files in the directory.
20. 
21. Do wiring.
22. Plug the ESP32 development board to your PC and wait for the drivers to install (or install manually any that might be required).
23. Open Arduino IDE. 
24. Open Boards manager. Go to Tools -> Board -> Boards Manager… (in our case it’s the DOIT ESP32 DEVKIT V1)
25. Select COM port that the board is attached to (if you don’t see the COM Port in your Arduino IDE, you need to install the ESP32 CP210x USB to UART Bridge VCP Drivers)
26. 
27. One DC motor without speed control (constant maximum speed only). Set the jumper on ENA and +5V on the motor driver board and the 5V_EN (5V) regulator jumper too. GPIO 14 is not in use.
28. Compile and upload the WithoutSpeedcontrolsketch1 to your ESP32 development board. If everything went as expected, you should see a “Done uploading” message. (You need to hold the ESP32 on-board Boot button while uploading).
29. Press the ESP32 on-board EN button to reboot it. 
    
30. One DC motor with speed control. Remove jumper on ENA and +5V from the motor driver board and set the 5V_EN (5V) regulator jumper on the motor driver board. GPIO 14 is in use.
31. Compile and upload the WithSpeedcontrolsketch2 to your ESP32 development board. If everything went as expected, you should see a “Done uploading” message. (You need to hold the ESP32 on-board Boot button while uploading).
32. Press the ESP32 on-board EN button to reboot it. 

Code

You can control the DC motor speed by applying a PWM signal to the enable pin of the L298N H-Bridge motor driver module. The speed will be proportional to the duty cycle. To use PWM with the ESP32 development board, you need to set the PWM signal properties first.

const int freq = 30000;

const int pwmChannel = 0;

const int resolution = 8;

int dutyCycle = 200;

In this case we’re generating a signal of 30000 Hz on channel 0 with a 8-bit resolution. We start with a duty cycle of 200 (you can set a duty cycle value from 0 to 255). For the frequency we’re using when you apply duty cycles smaller than 200, the motor won’t move and will make a weird buzz sound. So, that’s why we set a duty cycle of 200 at the start. PWM properties we’re defining here are just an example. The motor works fine with other frequencies.

You need to configure a PWM signal with the properties you’ve defined earlier by using the ledcSetup() function that accepts as arguments, the pwmChannel, the frequency, and the resolution. Next you need to choose the GPIO you’ll get the signal from. For that use the ledcAttachPin() function that accepts as arguments the GPIO where you want to get the signal, and the channel that is generating the signal. In this example, we’ll get the signal in the ENA GPIO, that corresponds to GPIO 14. The channel that generates the signal is the pwmChannel, that corresponds to channel 0.

To control the DC motor speed, we need to change the PWM signal duty cycle. For that you use the ledcWrite() function that accepts as arguments the PWM channel that is generating the signal (not the output GPIO) and the duty cycle. We have a while loop that increases the duty cycle by 5 in every loop. When the while condition is no longer true, we set the duty cycle to 200 again.

Summary

We have learnt how to control the direction and speed of a DC motor using an ESP32 development board and the L298N H-Bridge motor driver module.  

Libraries

• No libraries required for this project

Sketch

• See attachments on the begining of this project

Published at 03-09-2018
Viewed: 7035 times