This Optical Infrared Liquid Level Sensor is a solid-state fluid detection sensor designed to work with virtually any liquid medium, including water, oils, fuels, coolants, and chemicals. Unlike traditional mechanical float switches that can easily jam due to debris or rust, this sensor relies on the optical principles of total internal reflection and light refraction. It features no moving parts, providing long-term reliability for automated tank filling, water shortage alarms, and industrial fluid level monitoring systems.

Specifications

• Sensor Type: Optical infrared refraction (Non-mechanical, single-point measurements)
• Power Voltage: 5V DC
• Current Output: 15mA
• Measuring Accuracy: 1mm
• Cable Length: 50 cm
• Compliance: RoHS compliant
• Mounting Style: Threaded body with locking nut interface

Working Principle

The sensor housing contains an infrared light-emitting diode (LED) and a matching photosensitive receiver placed inside a clear conical prism tip.

• Dry State (No Liquid): When the sensor tip is surrounded by air, the infrared light emitted by the internal LED is totally reflected internally within the prism tip, bouncing straight back into the light receiver. The sensor outputs a stable digital logic state.
• Wet State (Liquid Present): When the conical prism tip becomes submerged in any liquid, the refractive index changes. The infrared light refracts out into the liquid rather than reflecting internally, causing the internal receiver to detect a loss of light. The sensor instantly toggles its digital output line to signal the presence of fluid.

Interface and Wiring Guide

• VCC (Red): 5V Power Supply Input
• GND (Black): Common Ground Reference
• OUT (Yellow/Blue): Digital Logic Signal Output (Connects to microcontroller GPIO)

Key Features

• No Mechanical Moving Parts: Eliminates mechanical jamming, sticking, or magnetic degradation, ensuring exceptionally high reliability and a long operational lifespan.
• Universal Fluid Compatibility: Detects virtually any liquid type (water, petroleum products, motor oil, hydraulic fluids, weak acids/alkalis) regardless of conductivity, color, or density.
• High Precision Level Control: Delivers single-point detection with an accuracy threshold down to 1mm.
• Safety Standard Certified: Built to meet safety standard requirements and carries full RoHS compliance for environmentally safe engineering installations.
• Leak-Proof Installation: Threaded housing and rubber washer with a locking nut allow secure, watertight bulkhead mounting through tank walls.

Common Applications

• Commercial & Household Appliances: Water dispensers, coffee machines, washing machines, and HVAC humidifiers.
• Automotive & Marine Equipment: Engine oil level monitoring, coolant reservoir sensing, and bilge water alarms.
• Industrial Fluid Tanks: Monitoring hydraulic oil reservoirs, lubricant lines, and chemical processing vats.
• Medical & Laboratory Devices: Tracking liquid waste, reagent bottles, and IV drip levels.

Usage Tips

• Optical Interference Protection: Avoid positioning the sensor tip in direct alignment with powerful external infrared sources or intense direct sunlight to prevent false triggering.
• Condensation and Bubble Management: If persistent air bubbles or heavy droplets stick to the prism tip, mount the sensor horizontally at a slight downward angle (15–45 degrees) to allow fluid or air to slide off cleanly.
• Chemical Compatibility: Ensure the housing plastic material (typically polycarbonate or polysulfone) is chemically compatible with the specific solvent or corrosive fluid being measured.