IR Slot Optical Speed Sensor Module FC-33 LM393 - Encoder Disc RPM Counter for Arduino

IR Slot Optical Speed Sensor Module FC-33 / LM393 - Encoder Disc RPM and Position Counter

Measure motor RPM, encoder disc position, and rotational speed with this compact slotted infrared optical sensor module. The FC-33 uses an IR photointerrupter (slotted optocoupler) paired with an LM393 comparator to deliver a clean digital pulse output every time an encoder disc or blade passes through the slot - making it ideal for speed measurement, position counting, and tachometer projects with Arduino and ESP32.

Key Features

• Slotted IR photointerrupter - detects encoder disc teeth or blades passing through the slot
• LM393 comparator IC - provides a clean, stable digital HIGH/LOW output signal
• Digital output - directly readable by Arduino, ESP32, Raspberry Pi, and any microcontroller
• LED indicator - lights when the slot is clear (no obstruction), off when blocked
• 3-pin header (VCC, GND, OUT) - standard 2.54mm pitch, breadboard and Dupont cable compatible
• Compact black PCB - easy to mount on motor shafts, wheels, and rotating assemblies
• Compatible with standard 20-slot encoder discs (sold separately)

Specifications

• Model: FC-33
• Comparator IC: LM393
• Sensor Type: Slotted IR photointerrupter (optocoupler)
• Supply Voltage: 3.3V - 5V DC
• Output Type: Digital (HIGH / LOW)
• Output Connector: 3-pin 2.54mm header (VCC, GND, OUT)
• Indicator: LED (lights when slot is unobstructed)
• PCB Color: Black

How It Works

• An IR LED and IR photodiode face each other across the slot gap
• When the slot is clear, IR light reaches the photodiode and output is HIGH
• When an encoder disc tooth or blade breaks the IR beam, output goes LOW
• The LM393 comparator sharpens the transition for clean digital pulse counting
• Count pulses per second to calculate RPM using known disc slot count

Perfect For

• Motor RPM and Speed Measurement with Encoder Disc
• Arduino and ESP32 Tachometer Projects
• Conveyor Belt and Wheel Speed Sensing
• Robotic Position and Revolution Counter
• Line Following Robot Wheel Odometry
• CNC and 3D Printer Encoder Feedback

Order now and add accurate digital speed and position sensing to your motor control or robotics project.