Blog

Tags : niveau d’eau, Zigbee, Tuya, Ewelink, Jeedom, Home Assistant, Zigbee2MQTT

Cet article est une collaboration commerciale non rémunérée avec Domadoo.

0. Context

Monitoring the water level in a tank or reservoir can be tedious. Opening the lid, checking manually, and guessing by eye are not practical solutions. The ME201WZ Wireless Level Sensor simplifies the process. This Zigbee ultrasonic sensor continuously measures the distance between itself and the surface of the water, transmitting the data directly to your home automation system.

Originally designed for Tuya and Smart Life, it integrates perfectly with Ewelink, Jeedom, Home Assistant, and Zigbee2MQTT. You can track your water level in real time, set up automatic alerts, and prevent overflows.

1. Technical specifications

• Model: ME201WZ

• Type: wireless ultrasonic water level sensor

• Protocol: Zigbee 3.0 – compatible with Tuya, Smart Life, Ewelink, Jeedom, Home Assistant, Zigbee2MQTT

• Measuring range: 0.1 to 4 meters

• Accuracy: ±2 cm typical

• Power supply: 12 V DC via supplied power adapter

• Consumption: ≤100 mA (≈0.5 W)

• Material: ABS with waterproof ultrasonic probe (IP65)

• Operating temperature: –20 °C to +70 °C

• Wireless range: about 50 meters in open field

2.1 Ideal placement

The ME201WZ uses ultrasound and requires a clear line of sight to the water surface. Install it above the tank, perfectly vertical, with nothing obstructing it. You can use a small open canopy or shield to protect it from sunlight or direct rain, but never cover the ultrasonic face.

Practical tips:

• Drill a 55 mm hole in the tank lid.

• Mount the sensor with its rubber gasket.

• Leave at least 10 cm between the sensor and the inner wall.

• Avoid placing it directly above the water inlet, as turbulence can cause inaccurate readings.

2.2 Power supply

The sensor runs on 12 V DC with the supplied adapter. Power consumption is below 1 W, allowing continuous use without issue. In damp environments, it is recommended to use a silicone cable and waterproof connector for the low-voltage section.

3. Pairing and compatibility

3.1 Zigbee inclusion

1. Connect the sensor to power.

2. Press and hold the touch button under the sensor for about five seconds until the red LED flashes quickly.

3. Start pairing on your Zigbee gateway (Tuya, Ewelink, Zigbee2MQTT, etc.).

4. The device will appear as ME201WZ Water Level Sensor.

3.2 Zigbee2MQTT configuration

Once paired, you can configure several parameters:

• installation_height → distance from sensor to bottom of the tank (in meters)

• liquid_depth_max → maximum water depth

• max_set / mini_set → high and low alert thresholds (in percent)

Example configuration:
{« installation_height »:1.95}
{« liquid_depth_max »:1.80}
{« max_set »:90, « mini_set »:20}

This setup provides an accurate display of the tank’s fill level in percentage.

Values reported automatically:

• liquid_depth: current depth (in meters)

• liquid_level_percent: water fill percentage

• liquid_state: low, normal, or high

3.3 Integration with Jeedom and Home Assistant

Using MQTT, the sensor’s values appear directly in your dashboards. All readings are available for automations or monitoring.

4. Example scenarios

4.1 Low salt tank refill notification

Trigger: level below 30 percent
Action: send a notification reminding you to refill the salt tank

4.2 High level overflow alarm

Trigger: level above 90 percent
Action: send a notification and automatically stop the pump

4.3 Smart irrigation

Trigger: fixed watering schedule
Conditions: soil humidity below 40 percent, no rain forecast, tank water level above 20 cm
Action: open the irrigation valve

4.4 Consumption tracking

Trigger: every day at 8 p.m.
Action: record the water level in a Jeedom virtual or Home Assistant graph

5. Pros and cons

Pros

• Ultrasonic, contactless measurement

• Simple installation

• Compatible with Tuya, Ewelink, Jeedom, Home Assistant, Zigbee2MQTT

• Accurate readings with low energy consumption

• High and low alerts configurable in Zigbee2MQTT

• IP65 waterproof probe

• Reasonable price (about 40–50 euros depending on version)

Cons

• Main housing not waterproof, must be protected from direct rain

• Requires drilling into the tank, unsuitable for fuel tanks or motorhomes

• Pairing can be finicky, must hold the button until fast flashing

• Average Zigbee range, metal structures can interfere

• Slight delay in measurement (1–2 seconds)

• Turbulent water surfaces can cause unstable readings, a deflector may be required

6. Conclusion

The ME201WZ Zigbee water level sensor is a practical and reliable solution for monitoring tanks and reservoirs. It is easy to install, accurate, and compatible with major smart home platforms.

Whether for a rainwater tank, pond, or cistern, it provides real-time monitoring and allows for automated refilling or irrigation. Its contactless ultrasonic design, simple integration, and stability with Zigbee2MQTT make it an excellent option.

With careful installation to avoid echo interference, it delivers consistent results. The need to drill the tank is a minor drawback compared to the precision it provides.

A solid and intelligent device for those who value practicality, automation, and energy efficiency.

Loïc