Adafruit
Optomax Digital Liquid Level Sensor
The Optomax is an optical liquid level sensor that detects the presence or absence of almost any liquid — oil or water based. Inside the polysulfone housing,...
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The Optomax is an optical liquid level sensor that detects the presence or absence of almost any liquid — oil or water based. Inside the polysulfone housing, an infrared LED and matching phototransistor work together: when dry, the IR light reflects internally back to the sensor; when the tip is immersed in liquid, the light escapes and the output switches.
The sensor provides a push-pull digital output capable of sinking or sourcing up to 100 mA, allowing it to directly drive small loads like transistors or relays. It operates on 4.5–15.4 V DC and is insensitive to ambient light, foam (when in air), and small bubbles (when in liquid).
Key Features
- Optical Sensing – No moving parts for reliable, maintenance-free operation
- Push-Pull Output – Sinks or sources up to 100 mA for direct load driving
- Wide Supply Range – 4.5–15.4 V DC with reverse polarity, ESD, and transient protection
- Chemical Resistant Housing – Polysulfone construction for use with a wide range of fluids
- Compact Form Factor – Suitable for space-constrained installations
- Leak Detection Capable – Sensitive enough to detect small amounts of liquid when positioned correctly
- Fast Response – Repeatable switching point with optional output delays for sloshing applications
Wiring
- Blue/Black Wire – Ground
- Red Wire – Supply voltage (4.5–15.4 V DC)
- Output – Supply voltage when dry, 0 V when wet
Specifications
- Output Type – Push-pull, up to 100 mA sink/source
- Supply Voltage – 4.5–15.4 V DC
- Housing Material – Polysulfone (chemically resistant)
- Operating Temperature – −25 °C to 80 °C
- Detection – Oil and water-based liquids
Package Contents
- 1× Optomax digital liquid level sensor
Jargon buster
Plain-language definitions for the technical terms used above.
- DC
- DC means direct current, where electricity flows in one constant direction, as supplied by batteries, USB ports and many plug-pack power supplies. When a product specifies DC, it runs from a DC supply rather than mains AC, so you need to provide the correct voltage and polarity.
- LED
- A light-emitting diode (LED) is a small electronic component that emits light when current flows through it in the correct direction. Because it only conducts one way, its polarity matters, and a through-hole LED must be soldered the correct way around to light up.
- phototransistor
- A light-sensitive transistor that changes its electrical output when light hits it. Compared with a modulated IR receiver, a simple phototransistor can be more affected by ambient light, so it may need extra filtering or careful setup.
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