Non-Contact Capacitive Water Level Sensor 3.3V–5V | Liquid Detector

Capacitive Non-Contact Water Level Sensor — Smart Liquid Detection Made Simple

Monitor liquid levels without ever touching the liquid. This compact capacitive water level sensor attaches to the outside of any plastic tank or container and detects whether it is full or empty — no drilling, no sealing, no corrosion. Running on just 3.3V–5V, it's the perfect addition to hand sanitizer dispensers, water coolers, aroma diffusers, DIY electronics projects, and more.

Key Features

• Non-contact detection — mounts flush against the outside wall of a plastic container; liquid never touches the sensor
• Wide voltage support — operates on 3.3V to 5V, compatible with Arduino, Raspberry Pi, and most microcontroller boards
• Dual alert function — provides both a low-water (water shortage) signal and a full-water reminder
• Color-coded wiring — Red = positive, Black = negative, Yellow = signal; quick and error-free connections
• Sheathed wire construction — durable, flexible cable for reliable long-term installations
• Dry-environment design — ideal for indoor use; keep away from high temperatures and moisture on the sensor body
• Compact & lightweight — easy to position and secure with minimal space required

Specifications

Compatible Use Cases

This sensor is well-suited for makers, hobbyists, and product developers working with:

• Arduino & Raspberry Pi water-level monitoring projects
• Automated hand sanitizer or soap dispenser refill alerts
• Aroma diffuser and humidifier low-water warnings
• Water cooler and countertop dispenser level control
• Custom IoT home automation systems

Important Notes

• Sensor must be used in close contact with the outer wall of a plastic water tank — it cannot detect through metal.
• Not suitable for detecting pure alcohol or gasoline.
• Use in a dry environment and avoid high-temperature conditions.
• Manual measurement tolerance: ±1–3 mm. Color may vary slightly from images due to screen settings.

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For more guidance on safe electronics and sensor use in DIY projects, visit the U.S. Consumer Product Safety Commission (CPSC) for general electrical product safety resources.

Frequently Asked Questions

Q: Can this capacitive water level sensor detect liquid through any container material?

A: No — the sensor is designed to work through plastic (non-metallic) container walls only. It cannot detect liquid through metal tanks or walls. For best results, press it flush against the outside of a thin plastic tank.

Q: Is this sensor compatible with Arduino and Raspberry Pi boards?

A: Yes! The sensor operates on 3.3V–5V DC, making it fully compatible with Arduino, Raspberry Pi, ESP32, and most other popular microcontroller platforms. Simply connect the red wire to power, black to ground, and yellow to your signal/input pin.

Q: What liquids can this sensor detect?

A: The capacitive liquid level sensor reliably detects water and most water-based liquids (such as liquid soap, diffuser water, and similar solutions). It cannot detect pure alcohol or gasoline due to their low dielectric constants.

Q: How do I install the sensor on my tank?

A: Clean and dry the outer wall of your plastic tank at the desired level. Position the sensor flat against the wall and secure it with tape or an adhesive mount. Connect the color-coded wires to your controller board, and the sensor will detect whether liquid is present at that point — no drilling or sealing required.