Overview:

The MOC7811 Slotted Opto Isolator Encoder Module is a non-contact position sensing device designed for precise object detection, rotational feedback, and motion sensing. It consists of an infrared emitter and a photodiode placed opposite each other inside a slotted housing. When an opaque object (like a rotary encoder disk or a tab) interrupts the infrared beam, the sensor outputs a signal change, making it highly effective for speed, direction, and position sensing in automation and robotics applications.

Features:

• Operating voltage: Typically 5V DC

• Infrared transmitter and photodiode in slotted configuration

• Non-contact sensing ensures long life and high reliability

• Outputs a clean digital signal when the IR beam is interrupted

• Compact and robust design suitable for embedded applications

• High response speed and sensitivity

Technical Highlights:

• Sensing method: Infrared slotted object detection

• Output type: Digital signal (based on beam interruption)

• Slot width: Approximately 5 mm

• Material: Durable black plastic housing

• Emission wavelength: Typically around 940 nm (infrared)

• Used for detecting interruptions in rotary encoders or slotted wheels

Pin Configuration:

• 4 pins total (two for IR LED and two for photodiode)

• LED side: Anode and Cathode

• Photodiode side: Collector and Emitter

• Often paired with a transistor or comparator circuit for usable output

Working Principle:

The MOC7811 module operates using a slotted opto-interruptive sensing technique. An IR LED emits light across the slot, which is received by a photodiode on the opposite side. When an object passes through the slot and blocks the IR beam, the photodiode output changes, indicating the presence or motion of the object. This change is detected by external circuitry or a microcontroller.

Applications:

• Rotary encoder feedback systems

• Motor speed and position detection

• Factory automation and robotics

• Printer mechanisms and CNC machines

• Slot-type object counters

• DIY electronics and motion-sensing projects

Advantages:

• Accurate and reliable position detection

• Ideal for rotational measurement and feedback loops

• Easy to integrate with microcontrollers and encoder disks

• Non-contact sensing reduces mechanical wear

• Affordable and simple to interface

Important Notes:

• Requires external circuitry (pull-up resistor or comparator) for clear output signal

• Keep sensor clean and free from dust to maintain accuracy

• Ensure correct pin identification before wiring

• Should be used with slotted encoder disks or tabs for motion detection

Datasheet and Resources:

• Official MOC7811 Datasheet (Components 101)