Table of Contents:

• 1. Introduction
  • 1.1 What is S31x-NB NB-IoT Temperature & Humidity Sensor
  • 1.2 ​Features
  • 1.3 Specification
  • 1.4 Applications
  • 1.5 Sleep mode and working mode
  • 1.6 Button & LEDs
  • 1.7 BLE connection
  • 1.8 Pin Definitions , Switch & SIM Direction
    • 1.8.1 Jumper JP2
    • 1.8.2 BOOT MODE / SW1
    • 1.8.3 Reset Button
    • 1.8.4 SIM Card Direction
  • 1.9 Hardware Variant
• 2. Use S31-NB to communicate with IoT Server
  • 2.1 Send data to IoT server via NB-IoT network
  • 2.2 ​Payload Types
    • 2.2.1 General Json Format(Type=5)
    • 2.2.2 HEX format Payload(Type=0)
    • 2.2.3 ThingsBoard Payload(Type=3)
    • 2.2.4 ThingSpeak Payload(Type=1)
  • 2.3 Test Uplink and Change Update Interval
  • 2.4 Multi-Samplings and One uplink
  • 2.5 Humidity and Temperature alarm function
  • 2.6 Trggier an uplink by external interrupt
  • 2.7 Clock logging (Since firmware version v1.2.1)
    • Unix TimeStamp
    • Poll sensor value
    • Datalog Uplink payload
  • 2.8 Example Query saved historical records
  • 2.9 Uplink log query
  • 2.10 Scheduled domain name resolution
  • 2.11 Set the QoS level
  • 2.12  Set CoAP option
  • 2.13 Print last few data entries
  • 2.14 Print data entries base on page
  • 2.15 Clear Flash Record
• 3. Configure S31x-NB
  • 3.1 Configure Methods
  • 3.2  Serial Access Password
  • 3.3 AT Commands Set
• 4. Battery & Power Consumption
• 5. Firmware update
• 6. FAQ
  • 6.1 How can I access t BC660K-GL AT Commands?
• 7. Order Info
• 8. ​Packing Info
• 9. Support

1. Introduction

1.1 What is S31x-NB NB-IoT Temperature & Humidity Sensor

The Dragino S31-NB and S31B-NB are NB-IoT Temperature and Humidity Sensor for Internet of Things solution. It is used to measure the surrounding environment temperature and relative air humidity precisely, and then upload to IoT server via NB-IoT network*.

The temperature & humidity sensor used in S31-NB is SHT31, which is fully calibrated, linearized, and temperature compensated digital output from Sensirion, it provides a strong reliability and long-term stability. The SHT31 is fixed in a waterproof anti-condensation casing for long term use.

S31-NB supports different uplink methods include TCP, MQTT, UDP for different application requirement. and Support Uplinks to various IoT Servers.

S31-NB is powered by 8500mAh Li-SOCI2 battery, It is designed for long term use up to several years. (Real-world battery life depends on the use environment, update period and uplink method. Please check related Power Analyze report).

*make sure you have NB-IoT coverage locally.

1.2 ​Features

• NB-IoT Bands: B1/B2/B3/B4/B5/B8/B12/B13/B17/B18/B19/B20/B25/B28/B66/B70/B85 @H-FDD
• Ultra-low power consumption
• External 3 meters SHT31 probe (For S31-NB)
• Measure range -40°C ~ 80°C
• Temperature & Humidity alarm
• Multiply Sampling and one uplink
• Support Bluetooth v5.1 remote configure and update firmware
• Uplink on periodically
• Downlink to change configure
• 8500mAh Battery for long term use
• Nano SIM card slot for NB-IoT SIM

1.3 Specification

Common DC Characteristics:

• Supply Voltage: 2.1v ~ 3.6v
• Operating Temperature: -40 ~ 85°C

Temperature Sensor:

• Range: -40 to + 80°C
• Accuracy: ±0.2 @ 0-90 °C
• Resolution: 0.1°C
• Long Term Shift: <0.03 °C/yr

Humidity Sensor: 

• Range: 0 ~ 99.9% RH
• Accuracy: ± 2%RH ( 0 ~ 100%RH)
• Resolution: 0.01% RH
• Long Term Shift: <0.25 %RH/yr

NB-IoT Spec:

NB-IoT Module: BC660K-GL

Support Bands:

• B1 @H-FDD: 2100MHz
• B2 @H-FDD: 1900MHz
• B3 @H-FDD: 1800MHz
• B4 @H-FDD: 2100MHz
• B5 @H-FDD: 860MHz
• B8 @H-FDD: 900MHz
• B12 @H-FDD: 720MHz
• B13 @H-FDD: 740MHz
• B17 @H-FDD: 730MHz
• B18 @H-FDD: 870MHz
• B19 @H-FDD: 870MHz
• B20 @H-FDD: 790MHz
• B25 @H-FDD: 1900MHz
• B28 @H-FDD: 750MHz
• B66 @H-FDD: 2000MHz
• B70 @H-FDD: 2000MHz
• B85 @H-FDD: 700MHz

Battery:

• Li/SOCI2 un-chargeable battery
• Capacity: 8500mAh
• Self Discharge: <1% / Year @ 25°C
• Max continuously current: 130mA
• Max boost current: 2A, 1 second

Power Consumption

• STOP Mode: 10uA @ 3.3v
• Max transmit power: 350mA@3.3v

1.4 Applications

• Smart Buildings & Home Automation
• Logistics and Supply Chain Management
• Smart Metering
• Smart Agriculture
• Smart Cities
• Smart Factory

1.5 Sleep mode and working mode

Deep Sleep Mode: Sensor doesn't have any NB-IoT activate. This mode is used for storage and shipping to save battery life.

Working Mode: In this mode, Sensor will work as NB-IoT Sensor to Join NB-IoT network and send out sensor data to server. Between each sampling/tx/rx periodically, sensor will be in IDLE mode), in IDLE mode, sensor has the same power consumption as Deep Sleep mode.

1.6 Button & LEDs

Note: When the device is executing a program, the buttons may become invalid. It is best to press the buttons after the device has completed the program execution.

1.7 BLE connection

S31x-NB support BLE remote configure and firmware update.

BLE can be used to configure the parameter of sensor or see the console output from sensor. BLE will be only activate on below case:

• Press button to send an uplink
• Press button to active device.
• Device Power on or reset.

If there is no activity connection on BLE in 60 seconds, sensor will shut down BLE module to enter low power mode.

1.8 Pin Definitions , Switch & SIM Direction

S31x-NB use the mother board from S31-NB which as below.

1.8.1 Jumper JP2

Power on Device when put this jumper.

Power off device when take out this jumper

1.8.2 BOOT MODE / SW1

1) ISP: upgrade mode, device won't have any signal in this mode. but ready for upgrade firmware. LED won't work. Firmware won't run.

2) Flash: work mode, device starts to work and send out console output for further debug

1.8.3 Reset Button

Press to reboot the device.

1.8.4 SIM Card Direction

See this link. How to insert SIM Card.

1.9 Hardware Variant

2. Use S31-NB to communicate with IoT Server

2.1 Send data to IoT server via NB-IoT network

The S31-NB is equipped with a NB-IoT module, the pre-loaded firmware in S31-NB will get environment data from sensors and send the value to local NB-IoT network via the NB-IoT module.  The NB-IoT network will forward this value to IoT server via the protocol defined by S31-NB.

Below shows the network structure:

There are two version: -GE and -1D version of S31-NB.

GE Version: This version doesn't include SIM card or point to any IoT server. User needs to use AT Commands to configure below two steps to set S31-NB send data to IoT server.

• Install NB-IoT SIM card and configure APN. See instruction of Attach Network.

• Set up sensor to point to IoT Server. See instruction of Configure to Connect Different Servers.  

Below shows result of different server as a glance.

1D Version: This version has 1NCE SIM card pre-installed and configure to send value to DataCake. User Just need to select the sensor type in DataCake and Activate S31-NB and user will be able to see data in DataCake. See here for DataCake Config Instruction.

2.2 ​Payload Types

To meet different server requirement, S31-NB supports different payload type.

Includes:

• General JSON format payload. (Type=5)

• HEX format Payload. (Type=0)

• ThingSpeak Format. (Type=1)

• ThingsBoard Format. (Type=3)

User can specify the payload type when choose the connection protocol. Example:

AT+PRO=1,0            // Use COAP Connection & hex Payload

AT+PRO=1,5            // Use COAP Connection & Json Payload

AT+PRO=2,0            // Use UDP Connection & hex Payload

AT+PRO=2,5            // Use UDP Connection & Json Payload

AT+PRO=3,0            // Use MQTT Connection & hex Payload

AT+PRO=3,5            // Use MQTT Connection & Json Payload

AT+PRO=4,0            // Use TCP Connection & hex Payload

AT+PRO=4,5            // Use TCP Connection & Json Payload

2.2.1 General Json Format(Type=5)

This is the General Json Format. As below:

{"IMEI":"863663062798914","Model":"S31x-NB","temperature":24.9,"humidity":51.8,"interrupt":0,"interrupt_level":0,"battery":3.35,"signal":17,"1":[0.0,0.0,"2024/05/29 05:51:27"],"2":[24.3,70.5,"2024/05/29 05:50:27"],"3":[24.3,70.5,"2024/05/29 05:49:27"],"4":[24.3,71.1,"2024/05/29 05:48:27"],"5":[24.2,70.3,"2024/05/29 05:47:27"],"6":[24.2,70.5,"2024/05/29 05:46:27"],"7":[24.1,71.6,"2024/05/29 05:43:58"],"8":[24.1,71.7,"2024/05/29 05:42:58"]}

Notice, from above payload:

• Temperature, Humidity, Interrupt, Interrupt_level, Battery & Signal are the value at uplink time.

• Json entry 1 ~ 8 are the last 1 ~ 8 sampling data as specify by AT+CLOCKLOG=1,65535,15,8  Command. Each entry includes (from left to right): Temperature, Humidity, Sampling time.

Example:

2.2.2 HEX format Payload(Type=0)

This is the HEX Format. As below:

f863663062798914007b0d021101Ffff000000000000f7020a6656c43300f902056656c3df000000006656c25f00f302c16656c22300f302c16656c1e700f302c76656c1ab00f202bf6656c16f00f202c16656c13300f102cc6656c09e

Version:

These bytes include the hardware and software version.

Higher byte: Specify Sensor Model: 0x00 for S31B-NB & S31-NB

Lower byte: Specify the software version: 0x7b=123, means firmware version 1.2.3

BAT (Battery Info):

Ex1: 0x0CBA = 3258mV

Signal Strength:

NB-IoT Network signal Strength.

Ex1: 0x16 = 22

0        -113dBm or less

1        -111dBm

2...30 -109dBm... -53dBm

31      -51dBm or greater

99      Not known or not detectable

DS18B20_Temperature:

Example: 0x00de(H)= 222(D) =22.2℃

Note: If the DS18B20 sensor is not connected, the hex payload is 0xFFFF and Serial port print: -409.5 ° C.

PA4_level:

Level of PA4 pin. (0: Low level     1: High level)

Interrupt:

This data field shows if this packet is generated by interrupt or not.

Example:

If byte[0]&0x01=0x00 : Normal uplink packet.

If byte[0]&0x01=0x01 : Interrupt Uplink Packet.

Interrupt_level:

This byte shows whether the interrupt is triggered by a high or low level.

Ex1: 0x00  Interrupt triggered by falling edge (low level)

Ex2: 0x01  Interrupt triggered by rising edge (high level)

Temperature: 

If payload is: 0105H:  (0105 & 8000 == 0), temp = 0105H /10 = 26.1 degree

If payload is: FF3FH :  (FF3F & 8000 == 1) , temp = (FF3FH - 65536)/10 = -19.3 degrees.

(FF3F & 8000: Judge whether the highest bit is 1, when the highest bit is 1, it is negative)

Humidity:   

Read:0295(H)=661(D)    Value:  661 / 10=66.1, So 66.1%

TimeStamp:   

Unit TimeStamp Example: 64d49439(H) = 1691653177(D)

Put the decimal value into this link(https://www.epochconverter.com/) to get the time.

2.2.3 ThingsBoard Payload(Type=3)

Type3 payload special design for ThingsBoard, it will also configure other default server to ThingsBoard.

{
    "topic": "2276492",
    "payload": {
        "IMEI": "863663062798914",
        "Model": "S31x-NB",
        "temperature": 26.0,
        "humidity": 70.8,
        "interrupt": 0,
        "interrupt_level": 0,
        "battery": 3.36,
        "signal": 21,
        "1": [204.8, 10.0, "2024/05/30 10:19:53"],
        "2": [204.8, 10.0, "2024/05/30 10:19:18"],
        "3": [204.8, 10.0, "2024/05/30 10:17:53"],
        "4": [204.8, 10.0, "2024/05/30 10:16:53"],
        "5": [204.8, 10.0, "2024/05/30 10:16:28"],
        "6": [204.8, 10.0, "2024/05/30 10:14:53"],
        "7": [204.8, 10.0, "2024/05/30 10:13:53"],
        "8": [204.8, 10.0, "2024/05/30 10:12:53"]
    }
}

2.2.4 ThingSpeak Payload(Type=1)

This payload meets ThingSpeak platform requirement. It includes only four fields. Form 1~4 are:

Temperature, Humidity, Battery & Signal. This payload type only valid for ThingsSpeak Platform

As below:

field1=Tem&field2=Hum&field3=BatV&field4=Singal

2.3 Test Uplink and Change Update Interval

By default, Sensor will send uplinks every 2 hours 

User can use below commands to change the uplink interval.

AT+TDC=7200        // Set Update Interval to 7200s

User can also push the button for more than 1 seconds to activate an uplink.

2.4 Multi-Samplings and One uplink

Notice: The AT+NOUD feature is upgraded to Clock Logging, please refer Clock Logging Feature

To save battery life, S31-NB will sample temperature & humidity data every 15 minutes and send one uplink every 2 hours. So each uplink it will include 8 stored data + 1 real-time data. They are defined by:

• AT+TR=900        // The unit is seconds, and the default is to record data once every 900 seconds (15 minutes, the minimum can be set to 180 seconds)

• AT+NOUD=8     //  The device uploads 8 sets of recorded data by default. Up to 32 sets of record data can be uploaded.

The diagram below explains the relationship between TR, NOUD, and TDC more clearly:

2.5 Humidity and Temperature alarm function

On each sampling define by AT+TR ( default 900s or 15 minutes), when the value exceed the range, it will trigger an Alarm and immediately sends a uplink. 

AT Commands:

AT+ SHHUM=min,max

Example: AT+ SHHUM=50,80     // Alarm when humidity lower than 50 or higher than 80.

AT+ SHTEMP=min,max

Example: AT+ SHTEMP=20,30   // Alarm when temperature lower than 20 or higher than 30

Notice:

• To disable Alarm, user can set min and max to same value , such as AT+SHTEMP=0,0.

• If user only want to send only min or max, user can set the alarm to a value that device won’t reach. For example: AT+SHTEMP=-80,0.

2.6 Trggier an uplink by external interrupt

S31-NB has an external trigger interrupt function. Users can use the PB15 pin to trigger the upload of data packets.

AT command:

• AT+INTMOD         // Set the trigger interrupt mode

• AT+INTMOD=0    // Disable Interrupt

• AT+INTMOD=1    // Trigger by rising and falling edge

• AT+INTMOD=2    // Trigger by falling edge

• AT+INTMOD=3    // Trigger by rising edge

2.7 Clock logging (Since firmware version v1.2.1)

Sometimes when we deploy lots of end nodes in field. We want all sensors sample data at the same time, and upload these data together for analyze. In such case, we can use clock loging feature.

We can use this command to set the start time of data recording and the time interval to meet the requirements of the specific collection time of data.

• AT command: AT+CLOCKLOG=a,b,c,d

a: 0: Disable Clock logging.   1: Enable Clock Logging

b: Specify First sampling start second: range (0 ~ 3599, 65535)         // Note: If parameter b is set to 65535, the log period starts after the node accesses the network and sends packets.

c: Specify the sampling interval: range (0 ~ 255 minutes)

d: How many entries should be uplink on every TDC (max 32)

Note: To disable clock recording, set the following parameters: AT+CLOCKLOG=1,65535,0,0

Example:

AT+CLOCKLOG=1,65535,1,5

After the node sends the first packet, data is recorded to the memory at intervals of 1 minute. For each TDC uplink, the uplink load will include: battery information + the last 5 memory records (payload + timestamp).

Note: Users need to synchronize the server time before configuring this command. If the server time is not synchronized before this command is configured, the command takes effect only after the node is reset.

• Downlink command: 0x0A

Format: Command Code (0x0A) followed by 5 bytes.

• Example 1: Downlink Payload: 0A01FFFF0F08             // Set SHT record time: AT+CLOCKLOG=1,65535,15,8
• Example 1: Downlink Payload: 0A0104B00F08             // Set SHT record time: AT+CLOCKLOG=1,1200,15,8

Note: When entering the downlink payload, there must be no Spaces between bytes.

Unix TimeStamp

S31x-NB uses Unix TimeStamp format based on

User can get this time from link:  https://www.epochconverter.com/ :

Below is the converter example

So, 1725875962 means that the current time is Monday, September 9, 2024 at 9:59 AM.

Poll sensor value

User can poll sensor value based on timestamps from the server. Below is the downlink command.

Timestamp start and Timestamp end use Unix TimeStamp format as mentioned above. Devices will reply with all data log during this time period.

For example, downlink command 31 66DE 6384 66DE 7194

Is to check 2024/9/9 02:55:00 to 2024/9/9 03:55:00's data

Datalog Uplink payload

The Datalog poll reply uplink will use below payload format.

Retrieval data payload:

Function Description: This feature is only used when the clock logging feature is turned on. one uplink packet can send 64 groups of stored data totaling 512 bytes.

Example(For MQTT.fx):

If user sends below downlink command: 

Where : Start time: 60065F97 = time 24/9/9 02:55:00

             Stop time: 66DE6A8C= time 24/9/9 03:25:00

S31x-NB will uplink this payload.

0x0100024966de638b 0100024866de63c7 00ff024d66de6403 00ff024b66de643f 00ff024666de647b 0100024b66de64b7 00ff024f66de64f3 00ff024566de652f

Temp=0x0100/10=25.6℃

Hum=0x0249/10=58.5%rh

Unix time is 0x66de638b =1725850507s=24/9/9 02:55:00

2.8 Example Query saved historical records

• AT command: AT+CDP

This command can be used to search the saved history, recording up to 32 groups of data, each group of historical data contains a maximum of 100 bytes.

2.9 Uplink log query

• AT command: AT+GETLOG

This command can be used to query upstream logs of data packets.

2.10 Scheduled domain name resolution

This command is used to set up scheduled domain name resolution

AT command:

• AT+DNSTIMER=XX  // Unit: hour

After setting this command, domain name resolution will be performed regularly.

2.11 Set the QoS level

This command is used to set the QoS level of MQTT.

AT command:

• AT+MQOS=xx   // 0~2

Downlink command: 0x07

Format: Command Code (0x07) followed by 1 byte.

Ex1: Downlink payload: 0x0700   //AT+MQOS=0

Ex2: Downlink payload: 0x0701   //AT+MQOS=1

2.12  Set CoAP option

This command sets the connection parameters of the COAP. 

AT command:

• AT+URI1       //CoAP option name, CoAP option length, "CoAP option value"
• AT+URI2      //CoAP option name, CoAP option length,  "CoAP option value"
• AT+URI3     //CoAP option name, CoAP option length,  "CoAP option value"
• AT+URI4     //CoAP option name, CoAP option length,  "CoAP option value"

Example:

• AT+URI1=11,38,"i/faaa241f-af4a-b780-4468-c671bb574858"

2.13 Print last few data entries

Feature: Print the last few data entries

AT command: AT+PLDTA

Downlink Command: 

No downlink commands for feature

2.14 Print data entries base on page

Feature: Print the sector data from start page to stop page.

AT command: AT+PDTA

Downlink Command: 

No downlink commands for feature

2.15 Clear Flash Record

Feature: Clear flash storage for data log feature.

AT command: AT+CLRDTA

Downlink Command:  0x32

• Example: 0x32 00        //  Same as AT+CLRDTA

3. Configure S31x-NB

3.1 Configure Methods

S31x-NB supports below configure method:

• AT Command via Bluetooth Connection (Recommended): BLE Configure Instruction.

• AT Command via UART Connection : See UART Connection.

3.2  Serial Access Password

After the Bluetooth or UART connection is successful, use the Serial Access Password to enter the AT command window.

The label on the box of the node will print the initial password: AT+PIN=xxxxxx, and directly use the six-digit password to access the AT instruction window.

If you need to change the password, use AT+PWORD=xxxxxx (6 characters), NB nodes only support lowercase letters.

Note: After entering the command, you need to add a line break, and you can also set automatic line breaks in the Bluetooth tool or UART connection tool.

3.3 AT Commands Set

AT+<CMD>?           : Help on <CMD>

AT+<CMD>                      : Run <CMD>

AT+<CMD>=<value>      : Set the value

AT+<CMD>=?          : Get the value

General Commands       

AT                    : Attention        

AT?                  : Short Help      

ATZ                 : MCU Reset     

AT+TDC          : Application Data Transmission Interval

AT+CFG          : Print all configurations

AT+CFGMOD           : Working mode selection

AT+DEUI                  : Get or set the Device ID

AT+INTMOD            : Set the trigger interrupt mode

AT+5VT           : Set extend the time of 5V power   

AT+PRO          : Choose agreement

AT+RXDL        : Extend the sending and receiving time

AT+DNSCFG   : Get or Set DNS Server

AT+GETSENSORVALUE   : Returns the current sensor measurement

AT+CLOCKLOG   : Get or set SHT record time

AT+CDP     : AT+CDP Read cached data/AT+CDP=0  Clear cached data

AT+SHTEMP:   Get or Set alarm of temp

AT+SHHUM:   Get or Set alarm of moisture

AT+SERVADDR :   Server Address

MQTT Management

AT+CLIENT               : Get or Set MQTT client

AT+UNAME              : Get or Set MQTT Username

AT+PWD                  : Get or Set MQTT password

AT+PUBTOPIC          : Get or Set MQTT publish topic

AT+SUBTOPIC          : Get or Set MQTT subscription topic

Information           

AT+FDR              : Factory Data Reset

AT+PWORD        : Serial Access Password

AT+LDATA           : Get the last upload data

AT+CDP               : AT+CDP Read cached data/AT+CDP=0  Clear cached data

COAP Management

AT+URI1            : Get or set CoAP option 1

AT+URI2            : Get or set CoAP option 2

AT+URI3            : Get or set CoAP option 3

AT+URI4            : Get or set CoAP option 4

Print or clear historical data

AT+PDTA           : Print the sector data from start page to stop page

AT+PLDTA         : Print the last few sets of data

AT+CLRDTA       : Clear the storage, record position back to 1st

4. Battery & Power Consumption

S31x-NB use ER26500 + SPC1520 battery pack. See below link for detail information about the battery info and how to replace.

Battery Info & Power Consumption Analyze .

5. Firmware update

User can change device firmware to::

• Update with new features.

• Fix bugs. 

Firmware and changelog can be downloaded from : Firmware download link

Methods to Update Firmware:

• (Recommended way) OTA firmware update via BLE: Instruction.

• Update through UART TTL interface : Instruction.

6. FAQ

6.1 How can I access t BC660K-GL AT Commands?

User can access to BC660K-GL directly and send AT Commands.

See BC660K-GL AT Command set

7. Order Info

Part Number: S31-NB-XX  / S31B-NB-XX

XX: 

• GE: General version ( Exclude SIM card)

• 1D: with 1NCE* 10 years 500MB SIM card and Pre-configure to DataCake server

1NCE SIM Card NB-IoT network coverage: Austria, Belgium, Bulgaria, Croatia, Czech Republic, Denmark, Finland, Germany, Great Britain, Greece, Hungary, Ireland, Italy, Latvia, Malta, Netherlands, Norway, Puerto Rico, Russia, Slovak , Republic, Slovenia, Spain, Sweden, Switzerland, Taiwan, USA, US Virgin Islands

8. ​Packing Info

Package Includes:

• S31-NB or S31-NB NB-IoT Sensor Node x 1

• External antenna x 1

Dimension and weight:

• Device Size: 13.0 x 5 x 4.5 cm

• Device Weight: 150g

• Package Size / pcs : 14.0 x 8x 5 cm

• Weight / pcs : 180g

9. Support

• Support is provided Monday to Friday, from 09:00 to 18:00 GMT+8. Due to different timezones we cannot offer live support. However, your questions will be answered as soon as possible in the before-mentioned schedule.

• Provide as much information as possible regarding your enquiry (product models, accurately describe your problem and steps to replicate it etc) and send a mail to Support@dragino.cc.