KY-003 Hall Effect Magnetic Sensor Module | ATMOSFÆR ENGINEERING

Digital magnetic field detector module using a Hall effect sensor to detect the presence of magnetic fields. Outputs digital HIGH when no magnet is present, LOW when a magnet (south pole) is detected nearby. Simple 3-pin interface for easy integration. Ideal for proximity sensing, position detection, speed measurement, door/window sensors, and non-contact switch applications.

Technical Specifications:

• Model: KY-003 Hall Magnetic Sensor
• Sensor Type: Hall Effect (digital output)
• Operating Voltage: 3.3V - 5V
• Output Type: Digital (HIGH/LOW)
• Detection: South pole of magnet triggers LOW output
• Sensitivity: Detects magnets within ~1.5cm range (varies by magnet strength)
• Output Current: Low current digital signal
• LED Indicator: Onboard LED (lights when magnet detected)
• Operating Temperature: -40°C to +85°C (typical)
• Module Dimensions: ~19mm x 15mm (typical KY-003 size)

Pin Configuration:

• S (Signal): Digital output pin
• • (VCC): Power supply (3.3V or 5V)
• • (GND): Ground

Output Behavior:

• No magnet: Output = HIGH (3.3V or 5V)
• South pole nearby: Output = LOW (0V)
• North pole: May not trigger or weak response (sensor is polarity-sensitive)

Features:

• Simple digital on/off output
• Onboard LED indicator for visual feedback
• 3.3V and 5V compatible
• No external components required
• Compact size
• Low power consumption
• Easy to use with any microcontroller

Applications:

• Magnetic proximity detection
• Door/window open/close sensors
• Non-contact switches
• Wheel rotation/speed sensors (with magnet on wheel)
• Position detection in actuators
• Security systems
• RPM measurement
• Contactless button replacement
• Flow meters (with magnetic impeller)
• Reed switch replacement (solid-state, no moving parts)

Typical Detection Range:

• Small neodymium magnet: ~5-15mm
• Larger/stronger magnets: up to 30mm
• Range depends on magnet strength and orientation

Usage Tips:

• Use south pole of magnet for reliable triggering
• Stronger magnets = longer detection range
• Mount magnet perpendicular to sensor face for best results
• Can be used to count rotations (magnet on rotating object)

Important Notes:

• Sensitive to south pole primarily (polarity matters)
• Not suitable for measuring magnetic field strength (digital only)
• For analog output, use KY-035 or similar analog Hall sensor
• LED indicator may increase power consumption slightly

Comparison:

• vs Reed Switch: No mechanical parts, faster response, longer lifespan
• vs KY-024 (Linear Hall): KY-003 is digital, KY-024 is analog
• vs KY-035: Similar but different IC, check specific trigger polarity

Compatible with Arduino, ESP32, Raspberry Pi, STM32, and any microcontroller with digital input pins. No special libraries required - simple digitalRead().