---
title: "DYP-L02 Ultrasonic Liquid Level Sensor – Technical Guide"
description: "The **DYP-L02 Ultrasonic Liquid Level Sensor** is designed for non-contact liquid level measurement and upper/lower level detection in sealed containers. Unlike conventional wetted liquid sensors, the L02 can operate from outside the container without drilling holes or placing a sensing…"
url: "https://plugplaykit.com/docs/dyp-l02-ultrasonic-liquid-level-sensor/"
updated: "2026-09-29"
category: Technical Support
---

# DYP-L02 Ultrasonic Liquid Level Sensor – Technical Guide

The **DYP-L02 Ultrasonic Liquid Level Sensor** is designed for non-contact liquid level measurement and upper/lower level detection in sealed containers.

Unlike conventional wetted liquid sensors, the L02 can operate from outside the container without drilling holes or placing a sensing element directly into the liquid.

When mounted underneath a container, it can measure liquid level height. When mounted on the outside wall of a container, it can detect whether liquid is present at a specific monitoring point.

This makes the sensor suitable for applications where direct contact with the liquid is undesirable or where the container needs to remain sealed.

---

## Key Features

The DYP-L02 provides:

- Non-contact liquid level measurement
- 2.8–5 V operating voltage
- 20–2000 mm liquid level measurement range
- 1 mm resolution
- Real-time tracking across the measurement range
- Multiple output configurations
- Adaptive blind-zone detection
- Operating temperature from -15°C to +60°C
- Storage temperature from -25°C to +80°C
- ESD protection compliant with IEC 61000-4-2
- Compact sensor design
- Automatic and triggered operating modes

The sensor uses an intelligent algorithm to identify container characteristics and automatically adapt its blind zone.

---

## Typical Applications

The L02 can be used for liquid detection through containers made from dense materials including:

- Steel
- Iron
- Glass
- Ceramic
- Non-foamed plastics

It is intended for clean, single-component liquids or miscible liquid mixtures without substantial sediment.

Typical applications include:

- Smart drinking cups
- Smart beer kegs
- Smart liquefied-gas systems
- Intelligent liquid-control equipment
- Sealed-container liquid monitoring

For reliable measurement, the container should have a reasonably regular shape and a relatively flat mounting surface.

---

## Technical Specifications

| Parameter | L023MUW | L023MTW | L023MGDW | L023MPNW |
| --- | --- | --- | --- | --- |
| Operating Voltage | 2.8–5 V | 2.8–5 V | 2.8–5 V | 2.8–5 V |
| Standby Current | 1 µA | 1 µA | 1 µA | 1–8000 µA |
| Average Current | 2.5–5 mA | 2.5–5 mA | 2.5–5 mA | 2.5–15 mA |
| Blind Zone | Adaptive | Adaptive | Adaptive | Adaptive |
| Liquid Level Range | 20–2000 mm | 20–2000 mm | 20–2000 mm | 20–2000 mm |
| Operating Cycle | 1 s | Triggered | 1 s | 1 s |
| Output | Automatic UART | Triggered UART | TTL Switching | PNP/NPN Switching |
| Resolution | 1 mm | 1 mm | 1 mm | 1 mm |
| Response Time | 1 s | 1 s | 1 s | 1 s |
| Repeatability Error | ±1 mm | ±1 mm | — | — |
| Measurement Angle | 3–12° | 3–12° | 3–12° | 3–12° |

For the UART models, room-temperature accuracy is specified as:

**±(5 + S × 0.5%) mm**

where **S** represents the current liquid level height.

Actual blind zone and measurement performance depend on the container material and wall thickness.

---

## Mechanical Dimensions

According to the mechanical drawing in the specification:

- Sensor diameter: **27.7 ± 0.5 mm**
- Sensor height: **17 ± 1 mm**
- Cable length: **300 ± 10 mm**

The sensor's compact form factor allows it to be mounted externally on suitable containers.

> ![](https://plugplaykit.com/wp-content/uploads/2026/09/Non-Contact-Ultrasonic-Liquid-Level-Sensor.png)

---

## Pin / Lead Definitions

The L02 uses four electrical connections:

| Pin | Lead | Description |
| --- | --- | --- |
| 1 | VCC | 2.8–5 V power input |
| 2 | GND | Power ground |
| 3 | TX/H | UART output / active-high TTL output / PNP output |
| 4 | RX/L | UART input / active-low TTL output / NPN output |

The function of TX/H and RX/L depends on the selected sensor model and output configuration.

> ![](https://plugplaykit.com/wp-content/uploads/2026/09/Non-Contact-Ultrasonic-Liquid-Level-Sensor-Packaging.png)

---

## Environmental Conditions

| Parameter | Minimum | Typical | Maximum |
| --- | --- | --- | --- |
| Storage Temperature | -25°C | 25°C | 80°C |
| Storage Humidity | — | 65% RH | 90% RH |
| Operating Temperature | -15°C | 25°C | 60°C |
| Operating Humidity | — | 65% RH | 80% RH |

Humidity specifications are non-condensing and vary according to ambient temperature.

---

## Electrical Conditions

| Parameter | Minimum | Typical | Maximum |
| --- | --- | --- | --- |
| Input Voltage | 2.8 V | 5 V | 5.25 V |
| Peak Current | — | — | 130 mA |
| Input Ripple | — | — | 50 mV p-p |
| Input Noise | — | — | 100 mV p-p |
| ESD | — | — | ±4 kV / ±8 kV |

The probe housing and output leads comply with **IEC 61000-4-2** for the stated ESD specification.

---

## UART Output

The L02 supports two UART operating modes depending on the selected model.

### Automatic UART

The sensor performs one measurement every second. The TX line automatically outputs the current measured liquid level.

### Triggered UART

A high-level pulse applied to RX initiates measurement on its falling edge. The sensor then outputs one liquid-level reading through TX.

The interval between triggers must be greater than **1 second**.

### UART Communication Settings

| Setting | Value |
| --- | --- |
| Signal Level | TTL |
| Data Bits | 8 |
| Stop Bits | 1 |
| Parity | None |
| Baud Rate | 9600 bps |

### UART Data Format

Each reading consists of four bytes:

| Field | Description | Length |
| --- | --- | --- |
| Header | Fixed value `0xFF` | 1 byte |
| Data_H | Upper 8 bits of distance data | 1 byte |
| Data_L | Lower 8 bits of distance data | 1 byte |
| SUM | Checksum | 1 byte |

The checksum is calculated as:

```
SUM = (Header + Data_H + Data_L) & 0x00FF
```

Example:

```
Header = 0xFF
Data_H = 0x07
Data_L = 0xA1
SUM    = 0xA7
```

Liquid level:

```
Liquid Level = Data_H × 256 + Data_L
             = 0x07A1
             = 1953 mm
```

Therefore, this example represents a measured liquid level of **1953 mm**.

---

### TTL Switching Output

#### Active-High Output

When liquid is detected:

- LED flashes once per second.
- TX output is at VCC.

When no liquid is detected:

- LED remains continuously on.
- TX output is 0 V.

The TTL output provides a logic-level signal only and **cannot directly drive a load**.

## Active-Low Output

When liquid is detected:

- LED flashes once per second.
- RX output is 0 V.

When no liquid is detected:

- LED remains continuously on.
- RX output is at VCC.

This output is also intended only as a high/low logic signal and cannot directly drive a load.

---

### PNP / NPN Switching Output

#### PNP Output

When liquid is detected, the internal transistor switches on and output H rises to VCC.

When no liquid is detected, the transistor switches off and output H is 0 V.

Use a resistive load drawing less than **100 mA**.

![](https://plugplaykit.com/wp-content/uploads/2026/09/Liquid-Level-Sensor-PNP-Switching-Output-1.png)

#### NPN Output

When liquid is detected, the internal transistor switches on and output L connects directly to GND.

When no liquid is detected, the transistor switches off and output L becomes an open circuit.

The resistive load must draw less than **100 mA**.

> ![](https://plugplaykit.com/wp-content/uploads/2026/09/Liquid-Level-Sensor-NPN-Switching-Output.png)

---

### LED Status Indicators

The sensor's LED provides a quick indication of its operating state:

| LED Status | Meaning |
| --- | --- |
| Continuously On | Sensor powered; no liquid detected |
| Slow Flashing | Liquid detected; flashes once per second |
| Triggered UART | Flashes once for every triggered measurement |

In triggered UART mode, the LED remains off when no measurement is being triggered.

---

### Choosing the Correct DYP-L02 Model

There are four L02 variants. The output configuration is determined at the factory; one sensor does **not** simultaneously support multiple output configurations.

| Model | Output / Function |
| --- | --- |
| **DYP-L023MUW-V1.0** | Automatic UART output |
| **DYP-L023MTW-V1.0** | Triggered UART output; 1 µA standby current |
| **DYP-L023MGDW-V1.0** | TTL high/low logic output; cannot drive a load |
| **DYP-L023MPNW-V1.0** | PNP/NPN output; load capability up to 100 mA |

### Which model should I use

For applications requiring continuous numerical liquid-level data, choose the **automatic UART model**.

For low-power systems where measurements are initiated only when required, use the **triggered UART model**.

For simple liquid-present/liquid-absent detection connected to a microcontroller, the **TTL version** provides a logic-level output.

For applications requiring a switching output capable of driving a resistive load up to 100 mA, use the **PNP/NPN version**.

---

### Reliability Testing

The L02 specification includes environmental, vibration and drop testing, including:

- 60°C / 85% RH powered operation for 72 hours
- -15°C powered operation for 72 hours
- 80°C / 80% RH storage for 72 hours
- -25°C storage for 72 hours
- 10–200 Hz vibration testing
- 1.2 m free-fall testing

After testing, the sensor must remain functional with performance degradation of no more than 10%.

---

### Important Installation and Usage Notes

Sensor performance depends on the actual container and installation conditions.

Keep the following points in mind:

1. Blind zone and maximum detectable liquid level vary with container material.
2. Container wall thickness also affects the blind zone and maximum detectable level.
3. Measurements can become unstable when the liquid level is outside the effective measurement range.
4. Significant movement or tilting of the liquid surface can affect readings.
5. Electromagnetic compatibility should be considered during system design.
6. Applications operating close to the sensor's limiting parameters should be evaluated carefully before final system integration.

---

### Packaging

Standard packaging is supplied by default.

Packaging materials may also be customized according to incoming quality control (IQC) requirements.