Introduction
In this project, we’ll build a smart DC motor controller using the SI9241AEY-T1-E3 IC. This chip is a high-side switch designed for automotive and industrial applications, making it ideal for controlling DC motors with precision and reliability. Our goal is to create a motor controller that allows for smooth speed control, direction switching, and safety features like overcurrent protection—all without complex microcontroller programming.By the end of this project, you’ll have a working DC motor driver that can be used in various applications like robotics, automated gates, and smart home appliances.
Components and Tools
Required Components:
● SI9241AEY-T1-E3 (High-side switch)● 12V DC Motor
● 12V Power Supply
● Potentiometer (10kΩ)
● Push Buttons (2x)
● LEDs (2x)
● Resistors (470Ω, 10kΩ)
● Diodes (1N4007)
● Capacitors (100µF, 0.1µF)
● Relay (12V, SPDT)
● Screw Terminal Blocks
● Breadboard or PCB
● Jumper Wires and Connectors
● Soldering Kit
Tools Required:
● Screwdriver● Multimeter
● Wire Strippers
● Soldering Iron
● Drill (if mounting on an enclosure)
Project Overview
The SI9241AEY-T1-E3 will act as the main control element for the DC motor. We’ll use a potentiometer to adjust the motor speed and two push buttons to change its direction. The relay will be used to reverse the motor polarity, while LEDs will provide visual feedback.Key Features of the Controller:
● Variable Speed Control using a potentiometer● Forward and Reverse Operation with push buttons
● Overcurrent Protection to prevent motor burnout
● LED Indicators for operation status
● Smooth Motor Operation with minimal electrical noise
Step-by-Step Build
Step 1: Setting Up the Power Supply
● Connect the 12V power supply to the circuit.● Attach a 100µF capacitor across the power terminals to stabilize voltage fluctuations.
Step 2: Wiring the SI9241AEY-T1-E3
● The SI9241AEY-T1-E3 will act as a switch to control the motor.● Connect its input pin to the potentiometer’s wiper to allow speed adjustments.
● The output pin will be connected to the motor through a relay.
● Attach a diode (1N4007) across the motor terminals to prevent voltage spikes.
Step 3: Adding Speed Control
● The potentiometer will control the voltage input to the SI9241AEY-T1-E3, adjusting the motor speed.● Turning the knob will increase or decrease the motor speed based on the resistance value.
Step 4: Implementing Direction Control
● We use a 12V SPDT relay to change the polarity of the motor, allowing it to switch between forward and reverse.● Two push buttons will activate the relay, flipping the motor direction.
● LEDs will indicate which direction the motor is moving.
Step 5: Adding Safety Features
● A 470Ω resistor is placed in series with the control input to protect against excessive current.● The SI9241AEY-T1-E3 has built-in thermal shutdown, preventing overheating.
● The relay ensures isolation from high current surges, preventing damage to the motor.
Testing and Troubleshooting
Step 6: Powering Up the Circuit
● Connect the 12V power supply and check for stable voltage.● Ensure the LED indicators light up correctly when pressing the direction buttons.
Step 7: Checking Motor Operation
● Slowly adjust the potentiometer and observe the motor speed change.● Press the direction buttons and verify that the motor switches direction.
Step 8: Fixing Common Issues
- Motor doesn’t turn on?
● Ensure the relay is functioning correctly.
- Speed control not working?
● Check for loose connections.
- Motor runs in one direction only?
● Ensure both push buttons are functional.
Final Assembly and Usage
Once tested, you can transfer the circuit to a PCB, solder the connections, and mount it inside an enclosure. You can use this motor controller for:● Robotic arms
● Automated conveyor belts
● Smart curtains and doors
US 19073 
BR 17100 
GB 13856 
CA 10663 
AU 8422 
IE 5969 
TR 2066 
NZ 1732 
