Dragino LHT65N/S-DC LoRaWAN Dry Contact Sensor Integration Guide

Model catalog

Search for these models in ThinkLink by name or ID.

Model type	Name	id_name	Platform model ID
RPC	[LHT65N-S-DC GET] 21313	lht65n_s_dc_get_21313	134064840598515716
RPC	[LHT65N-S-DC SET] 21313	lht65n_s_dc_set_21313	134064840598515715
Template	LHT65N-S-DC	LHT65N-S-DC_21313	134064840598515712
Thing Model	[LHT65N-S-DC]	lht65n_s_dc_21313	134064840598515713
Parameter Thing Model	[LHT65N-S-DC-PARA]	lht65n_s_dc_para_21313	134064840598515714

1. Sensor Overview

The Dragino LHT65N-DC and LHT65S-DC are LoRaWAN 1.0.3 Class A dry-contact sensors. They report switch state or interrupt events, a 32-bit pulse counter, internal temperature and humidity, battery health, and radio-link quality. The device joins by OTAA and uses a 2400 mAh non-rechargeable CR17450 Li-MnO2 battery.

Item	Value
Project	DRAGINO-21313-LHT65N-S-DC
Business code	21313
Vendor / Models	Dragino / LHT65N-DC, LHT65S-DC
Tenant	PUBLIC
Template	LHT65N-S-DC
Default region	CN470
Default uplink period	43200 s (12 hours)
Default downlink FPort	2

2. Product Features

1. Native LoRaWAN Class A operation without EdgeBus or an external DTU.
2. EXT=4 dry-contact state and interrupt reporting; EXT=8 32-bit pulse counting.
3. Both-edge, falling-edge, or rising-edge interrupt modes and selectable pulse-counting edge.
4. Temperature, humidity, battery voltage, and battery status in each real-time frame.
5. Device-information query for firmware, band, sub-band, and battery voltage.

3. Application Scope and Wiring

• Passive contacts from door sensors, relay outputs, leak detectors, smoke detectors, and SOS devices.
• Cumulative counting from low-power pulse sources such as flow sensors.
• Low-power sites that need contact events and ambient temperature/humidity together.

Passive contact: one wire to VCC/VDD, the other wire to INT
Powered pulse source: VCC to VCC/VDD, GND to GND, signal to INT

Verify that an externally powered input remains below 3.3 V before connecting it. Life-safety applications must not rely on this device or one wireless path alone.

4. Data Acquisition

4.1 FPort 2 Real-time Frame

The DC real-time payload is exactly 11 bytes in big-endian order:

Bytes	Field	Encoding and Conversion
0–1	battery_status, battery	top 2 bits status; low 14 bits mV; ÷1000 V
2–3	temperature	int16BE ÷100 °C
4–5	humidity	low 12 bits of uint16BE ÷10 %RH
6 bit7–4	no_ack, poll_message, time_sync_ok, unix_time_request	each 0/1
6 bit3–0	external_mode	0x04=interrupt, 0x08=counting
7	dry_contact_state	EXT=4; 1=closed, 0=open
8	interrupt_event	EXT=4; 1=interrupt, 0=periodic
7–10	pulse_count	EXT=8; uint32BE

Examples:

FPort 2: CBA40ABB025C0401017FFF
battery=2.980 V, battery_status=Good, temperature=27.47 °C,
humidity=60.4 %RH, external_mode=interrupt,
dry_contact_state=1, interrupt_event=1

FPort 2: CBA40ABB025C080000003C
external_mode=counting, pulse_count=60

The parser accepts only 11-byte frames with EXT=4 or EXT=8. It adds rssi, snr, and adr when gateway metadata supplies them.

4.2 FPort 5 Device Information

Bytes	Field	Encoding
0	sensor_model	fixed 0x0B
1–2	firmware_version	version nibbles
3	frequency_band	Dragino band enumeration
4	sub_band	0xFF=N/A
5–6	battery	uint16BE mV ÷1000 V

FPort 5: 0B01560BFF0BA4
sensor_model=LHT65N/S, firmware_version=1.5.6,
frequency_band=CN470, sub_band=N/A, battery=2.980 V

FPort 3 historical replay and non-DC external probes are outside this model.

5. EdgeBus Model

This is a native LoRaWAN sensor. It requires no EB code and sends data directly through the LoRaWAN network.

6. Thing Models

The lht65n_s_dc_21313 telemetry model processes FPort 2. The lht65n_s_dc_para_21313 parameter model processes FPort 5.

Field	Type	Unit	Meaning
battery	number	V	Battery voltage
battery_status	string	—	Ultra Low / Low / OK / Good
temperature	number	°C	Internal temperature
humidity	number	%RH	Internal humidity
external_mode	string	—	interrupt / counting
dry_contact_state	number	—	Contact state, EXT=4
interrupt_event	number	—	Interrupt origin, EXT=4
pulse_count	number	count	Cumulative count, EXT=8
no_ack / poll_message	number	—	Protocol flags
time_sync_ok / unix_time_request	number	—	Time flags
rssi / snr	number	dBm / dB	Gateway link quality
adr	boolean	—	Adaptive data-rate state

Core decoding logic:

const rawBattery = bytes.readUInt16BE(0);
const externalModeCode = bytes[6] & 0x0f;
telemetry.battery = Number(((rawBattery & 0x3fff) / 1000).toFixed(3));
telemetry.temperature = Number((bytes.readInt16BE(2) / 100).toFixed(2));
telemetry.humidity = Number(((bytes.readUInt16BE(4) & 0x0fff) / 10).toFixed(1));
if (externalModeCode == 0x04) {
    telemetry.dry_contact_state = bytes[7] ? 1 : 0;
    telemetry.interrupt_event = bytes[8] ? 1 : 0;
} else {
    telemetry.pulse_count = bytes.readUInt32BE(7);
}

7. Third-party Data Subscription

MQTT topic:

/v32/{Organization Account}/tkl/up/telemetry/{eui}

Example:

{
  "eui": "6353012af10a9331",
  "active_time": "2026-07-26T08:35:48.000Z",
  "thingModelId": "134064840598515713",
  "thingModelIdName": "lht65n_s_dc_21313",
  "telemetry_data": {
    "battery": 2.98,
    "battery_status": "Good",
    "temperature": 27.47,
    "humidity": 60.4,
    "external_mode": "interrupt",
    "dry_contact_state": 1,
    "interrupt_event": 1,
    "rssi": -72,
    "snr": 8.5
  }
}

8. RPC

8.1 Settings

lht65n_s_dc_set_21313 builds one Class A user downlink per invocation:

Setting	Parameter	Range	Downlink
Uplink period	period_up	1–16777215 s	01 + uint24BE
Both-edge interrupt	interrupt_both	—	A2 04 01
Falling-edge interrupt	interrupt_falling	—	A2 04 02
Rising-edge interrupt	interrupt_rising	—	A2 04 03
Falling-edge counting	counting_falling	—	A2 08 01 00
Rising-edge counting	counting_rising	—	A2 08 01 01
Set cumulative count	pulse_count	0–4294967295	A2 08 02 + uint32BE

period_up=43200 -> 01 00 A8 C0
pulse_count=60  -> A2 08 02 00 00 00 3C

8.2 Device-information Query

lht65n_s_dc_get_21313 always sends 26 01. The device returns its information on a later FPort 5 uplink.

A Class A device normally receives a downlink only in receive windows following an uplink. RPC completion confirms downlink construction and submission, not that the device has applied a setting.

9. Template Selection

Select this PUBLIC template:

• Template: LHT65N-S-DC
• id_name: LHT65N-S-DC_21313
• Template ID: 134064840598515712

Template defaults:

Attribute	Default
class_mode	ClassA
standard	CN470
period_up	43200 s
downlink_port	2
external_mode	interrupt_both
pulse_count	0

Register the OTAA device with the DevEUI, JoinEUI/AppEUI, and AppKey from its label; never store keys in the integration project. Match the band to the firmware and network. After first join, request device information to verify the band and firmware.

10. Testing and Additional Notes

The local test/lht65n_s_dc.test.mjs suite covers EXT=4, EXT=8, negative temperature, status flags, invalid port/length/EXT, FPort 5, all SET commands, GET, and JSON/template/index consistency.

Official references:

• https://www.dragino.com/products/lorawan-nb-iot-door-sensor-water-leak/item/328-lht65n-s-dc.html
• https://wiki.dragino.com/docs/LoRaWAN-End-Node/temperature-humidity-sensors/lht65n/
• https://wiki.dragino.com/docs/Configuration/end-node/lht65n-dc-connection-instruction/
• https://github.com/dragino/dragino-end-node-decoder/tree/main/LHT65N