How to use Mosfet Optocoupled HW-532 to control up to 30V DC Motor Speed or load using Arduino
This project guide demonstrates how to build a versatile DC motor speed controller using an Arduino and the HW-532 optocoupled MOSFET module. The mosfet may be FR120N , LR7843 or D4184. This allows you to control the speed and on/off state of a DC motor with voltages up to 30V. The HW-532 module offers protection and isolation, making it safer and more reliable than directly connecting the motor to the Arduino.

This project is valuable for various applications. Here are a few examples:
- Precisely controlling the speed of a robotic arm
- Building a variable-speed fan for cooling systems
- Creating automated machinery with adjustable movement
- Developing a motorized valve control for fluid systems
Hardware/Components
The core components are the Arduino, the HW-532 optocoupled MOSFET module (with MOSFET options like D4184, LR7843, or FR120N), a DC motor (voltage rating ≤ 30V), connecting wires, and optionally, a potentiometer and push-button switch for advanced control (in video at 19:34).
The choice of MOSFET within the HW-532 module depends on your current requirements (in video at 01:24). The video provides a detailed comparison of the different MOSFETs (in video at 06:50) and their suitability for various applications (in video at 09:45). Remember to include a diode for inductive loads like DC motors to protect the module (in video at 06:00 and 22:02).
Wiring Guide
The basic wiring connects the motor's positive terminal to the HW-532's output, the motor's negative terminal to the HW-532's ground, and the HW-532's control pin to an Arduino digital pin (in video at 11:16).

Code Explanation
The provided code offers three levels of control:

- On/Off Control: This simple code (in video at 15:05) uses a digital pin to switch the motor on and off. The user-configurable part is the
MOTOR_OUT_PINconstant, which defines which Arduino pin controls the HW-532 module. - PWM Speed Control: This code (in video at 15:39) uses Pulse Width Modulation (PWM) to control the motor's speed. The user can adjust
SPEED_MAXandSPEED_MINto set the upper and lower limits of the speed control, and themotorControl()andstopMotor()functions are used to control the motor and stop it, respectively. - Potentiometer and Push-Button Control: This code (in video at 22:12) allows controlling the motor speed with a potentiometer and starting/stopping it with a push button. User-configurable parts include
POT_PIN(potentiometer pin),MOTOR_OUT_PIN(PWM control pin),START_STOP_PIN(push button pin),SPEED_MAX, andSPEED_MIN.
Live Project/Demonstration
The video demonstrates the operation of all three code examples. The on/off control is shown (in video at 11:41), followed by PWM speed control (in video at 16:53), and finally, the potentiometer and push-button control (in video at 23:02).
Chapters
- [00:00] Introduction and Project Overview
- [01:24] HW-532 Module and MOSFET Options
- [03:23] Circuit Schematic and Explanation
- [05:11] Component Details
- [06:50] MOSFET Datasheet Analysis
- [11:16] Basic Wiring and On/Off Demonstration
- [15:05] Arduino Code for On/Off Control
- [15:39] Arduino Code for PWM Speed Control
- [19:34] Wiring with Potentiometer and Push Button
- [22:12] Arduino Code with Potentiometer and Push Button
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Things you might need
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AmazonPurchase HW-532 from Amazonamzn.to
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eBay
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AliExpressPurchase FR120N Motor Driver from AliExpresss.click.aliexpress.com
Resources & references
No resources yet.
Files📁
Datasheet (pdf)
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infineon-IRLR7843 LR7843 MOSFET datasheet
infineon-irlr7843-datasheet-en.pdf0.37 MB
Fritzing File
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HW-532B Mosfot Module
HW-532B.fzpz0.01 MB
Other files
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infineon-irfr120n-datasheet-en
infineon-irfr120n-datasheet-en.pdf0.39 MB -
alpha-and-Omega-AOD4184A_datasheet
alpha-and-Omega-AOD4184A_datasheet.pdf0.43 MB