Milesight Sensor WS303-868M

Milesight WS303 is a smart water leak detector with two stainless steel probes that detect water as low as 0.5 mm. It features a built-in buzzer for local alerts, sends notifications through LoRaWAN, and offers up to 5 years of battery life. Its compact IP67 design allows installation even in hard-to-reach places.

General configuration

Overview
For sensor configuration, use the Milesight ToolBox mobile application, available on both:

• Apple App Store: https://apps.apple.com/us/app/milesight-toolbox/id1518748039
• Google Play Store: https://play.google.com/store/apps/details?id=com.ursalinknfc&hl=en&pli=1

QR code – Milesight ToolBox

Installation and configuration

• Configuration is done via NFC.
• After reading the device, go to the Basic Information tab to update the Device Time.
• Setting the correct date and time is required for all devices.

LoRaWAN connection

• Devices are preconfigured with an AppKey for OTAA (default values are listed in the user manual).
• The gateway must be set to Public. If the gateway is configured as Private, devices will not be able to join the network.

Power supply

Type	Value
Power	CR2450 battery

LoRaWAN configuration

Parameter	Value
Join type	OTAA
AppEUI	24E124C0002A0001
AppKey	5572404C696E6B4C6F52613230313823

Data Encoding & Decoding

Type	GitHub Link
Decoder	View decoder
Encoder	View encoder
Codec	View codec

Technical Specifications

Parameter	Value
Wireless Transmission
Technology	LoRaWAN®, Milesight D2D
Antenna	Internal
Frequency	CN470 / IN865 / RU864 / EU868 / US915 / AU915 / KR920 / AS923-1&2&3&4
Tx Power	16 dBm (868MHz) / 20 dBm (915MHz) / 19 dBm (470MHz)
Sensitivity	-137 dBm @300bps
Mode	OTAA / ABP Class A
Leakage Detection
Liquid Type	Conductive liquid
Trigger Condition	≥ 0.5 mm liquid level
Others
Buzzer	Yes
Configuration	NFC App / Downlink
Advanced Features	D2D Controller, Water Leakage Alarm
Physical Characteristics
Power Supply	1 × CR2450 (590 mAh)
Battery Life	~5.7 years (typical use, 25°C)
Operating Temp	-10°C ~ +60°C
Humidity	0%–100% RH (non-condensing)
Ingress Protection	IP67
Dimensions	63 × 63 × 14 mm
Weight	36.4 g (incl. battery)
Material	ABS+PC, White
Installation	3M Tape / Desktop
Approvals	CE, FCC, RoHS

Integration resources and distribution links

Resource	Link
HARDWARIO Store	https://www.hardwario.store/p/milesight-ws303
Official page	https://www.milesight.com/iot/product/lorawan-sensor/ws303