The SenseCAP Sensor Hub 4G Data Logger can connect to any third party MQTT server — not just SenseCAP Cloud. You configure the server address, port, and MQTT credentials using the SenseCAP Configuration Tool, then switch the device to third party MQTT mode via its built-in CLI. This guide walks through the full process step by step, using our dedicated Ubidots+SenseCAP MQTT broker as the example platform.
Requirements
Before you begin, make sure you have the following ready:
SenseCAP Sensor Hub 4G Data Logger with at least one RS485 sensor connected
Micro SIM card with an active data plan, installed in the device
4G antenna attached to the device
USB-to-TTL serial cable (included with the SensorHub or purchased separately)
A Windows, macOS, or Linux computer
An active Ubidots account — you'll need your Ubidots API Token, which you can find under User Profile > API Credentials in your Ubidots dashboard
Step 1 — Install the SenseCAP Configuration Tool
The SenseCAP Sensor Hub Configuration Tool NG is a desktop application used to configure your device via a serial (USB-to-TTL) connection.
You may also need to install the USB-to-TTL driver if your system doesn't recognize the cable. Download the driver from the SenseCAP Drivers repository.
Step 2 — Connect the USB-to-TTL Cable
Locate port B6 on the bottom of the SensorHub — this is the combined power and serial port.
Connect the USB-to-TTL cable to port B6.
Plug the USB end into your computer.
Make sure the SensorHub is powered on.
Tip: If this is the first time powering on the device, the LED will stay on for about 5 seconds, turn off, then come back on after ~90 seconds once the boot process completes.
Step 3 — Read the Current Device Settings
Open the SenseCAP Sensor Hub Configuration Tool NG.
Select the correct COM port from the dropdown (the one corresponding to your USB-to-TTL cable).
Check the option "Enter configuration mode automatically on device's booted"
Click CONNECT, then GENERAL SETTINGS
You should see a settings panel appear with the current device configuration.
Step 4 — Configure the MQTT Broker
This step has two parts: first you enter the MQTT broker credentials in the GUI, then you switch the device from SenseCAP Cloud to third party MQTT mode via the command-line tool. These steps apply to any custom MQTT broker — we use Ubidots as the example here.
Part A — Enter MQTT credentials and APN
In the settings panel, enter the MQTT details:
Field | Value |
Server Address |
|
Server Port |
|
Username | The part of your token before the dash (e.g. |
Password | The part of your token after the dash (e.g. |
Also set the APN for your SIM card provider (required for cellular data). Your carrier's APN can usually be found on their website.
Click Write to save the settings to the device.
Where to find your Ubidots API Token
Log in to Ubidots, click your profile avatar, then go to API Credentials. Your token looks like BBUS-xxxxxxxxxxxx — enter BBUS as the Username and everything after the dash as the Password.
Part B — Switch to 3rd party MQTT via the command-line tool
Writing the credentials is not enough on its own — the device also needs to be told to stop using SenseCAP's default cloud and connect to a 3rd party MQTT server. This is done through the device's built-in command-line tool.
Power cycle the device while keeping the serial port open.
Keep the option "Enter configuration mode automatically on device's booted" checked.
Watch the serial console until being prompted for a command, then type "x", then select "[1] General cfg mode" by typing "1".
4. The device will boot into configuration mode and show a menu. Type b and press Enter to choose the cloud platform
5. Type 2 and press Enter to select 3rd party MQTT.
Power cycle your device, it will now connect to sensecap.ubidots.com instead of SenseCAP's default servers.
Step 5 — Power Cycle and Wait for First Upload
Disconnect the USB-to-TTL cable.
The device will go through its boot cycle:
LED on for 5 seconds, then off — hardware initialization
LED on after ~90 seconds — boot complete
LED stays on for ~4 minutes — first data collection and upload
LED turns off — device enters its normal collection interval
After the first upload cycle completes (about 5–6 minutes total), your data should appear in Ubidots.
Note: The default data upload interval may be set to 60 minutes. If you want more frequent updates during testing, change the Data Interval in the Configuration Tool before disconnecting (minimum: 1 minute).
Log in to your Ubidots account.
Navigate to Devices in the left sidebar.
Look for a device named SenseCAP Hub XXXXXX, where
XXXXXXare the last 6 characters of your Device EUI.
Your device is automatically provisioned with:
A friendly device name and icon
Named variables for each sensor measurement (e.g., Air Temperature, Air Humidity, CO2, Soil Moisture)
Units set for each variable (°C, %RH, ppm, etc.)
Battery level and Signal Strength (RSSI) as separate time-series variables
Device properties like firmware version and sample interval
All of this happens automatically on the first data upload — no manual configuration needed in Ubidots.
Step 6 — Build a Dashboard
Go to Data > Dashboards in Ubidots.
Click Add new Dashboard and give it a name (e.g., "SenseCAP Field Monitoring").
Add widgets:
Line chart — for temperature, humidity, or CO2 over time
Gauge — for battery level or signal strength
Metric — for the latest value of any variable
Map — if you've set a device location
For detailed instructions, see how to create a static dashboard or the Ubidots Dashboard documentation.
Troubleshooting
Verifying the connection via the serial log
The most reliable way to confirm your device is connecting to the right server is to read the boot log over the serial port. With the USB-to-TTL cable connected and the COM port open in the Configuration Tool, power cycle the device (unplug and replug the power cable). The device will print its full boot sequence to the serial console.
Look for a section like this:
>ST NETWORKICCID: 89577603240262763547net rssi: -51network latency: 22ms>ST APP OTAOTA elapse: 4s>ST CONNECT SERVER[2026/04/07 23:11:04] need get tokenserver_url: 149.248.198.96server_port: 1883
The key field to check is server_url. If your configuration was saved correctly, it should show 149.248.198.96 — the IP address that sensecap.ubidots.com resolves to at the time of writing. If it shows a different IP (SenseCAP's default servers), the broker settings were not saved — go back to Step 4 and repeat the configuration.
You can also confirm the network is working by checking net rssi (signal strength) and network latency. A poor signal (e.g. rssi worse than -90 dBm) may cause intermittent connection failures.
Device not appearing in Ubidots
Check your SIM card: Make sure it has an active data plan and is properly seated. The SensorHub requires a Micro SIM.
Verify APN settings: Some carriers require custom APN configuration. Set this in the Configuration Tool under General Settings.
Check the LED: If the LED never turns on after 90 seconds, the device may not be booting correctly. Ensure the antenna is attached and the SIM is installed.
Check the interval: If the data interval is set to 60 minutes, you may need to wait up to an hour for the first upload. Reduce the interval for faster testing.
Authentication errors / data not arriving
Double-check your credentials: The Username must be the part of your token before the dash (e.g.
BBUS), and the Password must be everything after the dash.Verify the broker address: Server address must be exactly
sensecap.ubidots.comand port must be1883.Check the platform setting: Make sure you completed Part B of Step 4 and selected option 2 (3rd Party MQTT) via the command-line tool — writing credentials alone is not enough.
Variables showing with raw labels instead of names
This can happen if the device was created before the Ubidots bridge was updated. Delete the device from Ubidots and let the SensorHub reconnect — the variables will be recreated with proper names, units, and icons.
Reverting to SenseCAP Cloud
Connect the USB-to-TTL cable and open the Configuration Tool.
Power cycle the device and press
cwithin 2 seconds to enter the command-line tool.Type
x, then select1for General cfg mode.Type
b, then select1for SenseCAP Cloud.
Supported Sensors and Variables
The SenseCAP Sensor Hub 4G supports up to 32 RS485 MODBUS sensors simultaneously across 4 data channels. When connected to an IoT platform like Ubidots via MQTT, sensor measurements are automatically provisioned as named variables with units — no manual setup required. The following environmental monitoring sensors are recognized:
Sensor Measurement | Ubidots Variable Name | Unit |
Air Temperature | Air Temperature | °C |
Air Humidity | Air Humidity | %RH |
Light Intensity | Light Intensity | Lux |
CO2 | CO2 | ppm |
Barometric Pressure | Pressure | hPa |
Soil Temperature | Soil Temperature | °C |
Soil Moisture | Soil Moisture | %RH |
Wind Speed | Wind Speed | m/s |
Wind Direction | Wind Direction | ° |
Rainfall (Hourly) | Rainfall (Hourly) | mm/h |
pH | pH | pH |
Dissolved Oxygen | Dissolved Oxygen | mg/L |
Electrical Conductivity | Electrical Conductivity | dS/m |
Soil VWC | Soil Volumetric Water | % |
PM2.5 | PM2.5 | ug/m3 |
PM10 | PM10 | ug/m3 |
Additionally, the following device status fields are captured:
Field | Type | Description |
Battery | Variable (%) | Battery level as a time-series variable |
Signal (RSSI) | Variable (dBm) | Cellular signal strength as a time-series variable |
Firmware Version | Device Property | Stored on the device object |
Sample Interval | Device Property | Stored on the device object |
Frequently Asked Questions
Can the SenseCAP Sensor Hub 4G connect to any MQTT broker?
Yes. The SenseCAP Sensor Hub 4G supports connecting to any third party MQTT server, not just SenseCAP Cloud. In the device's CLI, select option 2 ("3rd party MQTT") and enter your broker's address, port, username, and password in the Configuration Tool. Beware: your broker must be configured to support the expected payload and topics determined by SenseCAP. See their official documentation for more details about this.
What MQTT credentials does the SenseCAP Sensor Hub need?
The device requires a server address, port, username, and password. The exact values depend on your MQTT broker. For Ubidots, set the address to sensecap.ubidots.com, port 1883, username to your token prefix (e.g. BBUS), and password to the token suffix.
How do I configure the APN on the SenseCAP 4G data logger?
In the SenseCAP Configuration Tool, go to General Settings and enter your carrier's APN. This is required for the device's 4G cellular modem to connect to the internet. Your carrier's APN is usually listed on their website or support page.
Why is my SenseCAP 4G not connecting to my MQTT server?
The most common causes are: incorrect credentials, missing APN configuration, or forgetting to switch the device to third party MQTT mode via the CLI (Step 4 Part B). Use the serial log to verify the server_url field points to your broker's IP address — see the Troubleshooting section above.
How do I switch back from a custom MQTT broker to SenseCAP Cloud?
Connect the USB-to-TTL cable, power cycle the device, enter the CLI by pressing c within 2 seconds, type x, select 1 for General cfg mode, then type b and select 1 for SenseCAP Cloud.
What is the default data upload interval on the SenseCAP Sensor Hub?
The default upload interval is typically set to 5 minutes. You can change it in the Configuration Tool under General Settings. The minimum interval is 1 minute, which is useful during testing and initial setup.
What's Next?
Set up alerts: Configure Ubidots Events to get email or SMS notifications when values cross thresholds (e.g., soil moisture too low, CO2 too high).
Add more devices: Each SenseCAP SensorHub is automatically recognized by Ubidots as a separate device — just configure the MQTT broker on each unit and they'll appear automatically.
Integrate with other systems: Use Ubidots' webhook events or API to push data to your existing ERP, irrigation controller, or reporting system. Browse more device connection guides in our Help Center.
Need help? Contact Ubidots Support or visit the Ubidots Community.