SD card slot (all data is backed up here before being transmitted)


Sensor interface module (connect either the mini sensor interface module or large sensor interface module)


Power input


Cellular antenna connector


Communication activity LED (slow blink when connected, fast blink when no connection)


Test message button immediately starts data transmission so operation can be verified while on site

Mini sensor interface module
Optional larger sensor interface module

12 VDC output


5 VDC output


4 Analog channel inputs, (0-5 VDC and 4-20 mA)


0-5 VCD alarm output


5 VDC output


24/switched VDC output


Pulse input (rain gage)


SDI-12 input (expandable, up to 12 sensors)


12 VDC output

eTracker is the gateway between the sensors and the cloud. Data communication and IT infrastructure are merged under one user interface experience. eTracker was designed from the ground up to embrace the current and future trends of cloud-based remote data acquisition and the “Internet of Things” (IoT) revolution. This paradigm shift centralizes all the historically isolated processes of remote configuration, programming, logging, and telemetry. Configuration, logging, data processing and analysis is now done in the cloud, eliminating time and cost in programming and maintaining expensive, complex data loggers and communication devices at each remote location.

  • Direct Internet compliant data stream using HTTP/HTTPS.
  • Sensor measurements stored on easily-accessible SD card.
  • Cloud logging: all sensor data is forwarded to the cloud for processing, logging, retrieval and resulting action.
  • Integrated sensor interface with ports: 4 analog, 4 pulse, SDI-12 (up to 62 SDI-12 sensors).
  • Approximately 20X typical improvement in power consumption vs. typical cellular telemetry.
  • Intelligent data management, data buffering, and network verification to ensure successful transmission of critical data.

Unique Features

  • Link sensors to the cloud: Sensor data is linked directly to the cloud-based Amazon service or user’s server via the cellular network using HTTP or HTTPS (optional FTP available).
  • Unified data interface experience: Sensor configuration, data storage, custom algebraic equations, custom data formats and forwarding, control, analysis, alarm notifications (email, SMS), reporting and actions all done with one simple cloud-based user interface.
  • Easy configuration: Configure with any device connected to the Internet via the cloud-based Stevens-Connect. No custom programming or scripts required.
  • Automated updates: Updates to firmware and cloud-based application can be automatic.
  • Security: Three user access levels for configuration, data management interface and visualization. Data is saved on SD card and on the secured and redundant Amazon Cloud Services. Optional data encryption available.
  • Connection verification: eTracker verifies connection with cell network and server connection before data is sent. If no connection is available or if data reception is not confirmed, data is saved and sent the next scheduled transmission.
  • True cloud data service experience: Your data is sent directly and securely to the Amazon cloud- based service. No back-end database hosting or web server controlled by Stevens in which data flow takes a detour to the cloud.
  • Data format flexibility: Optionally forward data in various formats for third party so ware platforms, like Aquarius or WISKI, and in other formats such as binary, pseudo-binary, SHEF, and more.
  • Power control: Power cycle commands automatically initiated with the Stevens’ SOLO power management system.
  • Direct data access options: Third-party programs can access data using REST API or HTTP post.

Dead simple setup and configuration.

Configure anytime, anywhere, with any device.

All configuration and programming of the remote eTracker is done online via the cloud-based Stevens-Connect. Setup in 3 steps:


Connect sensors.


Connect to power source.


Configure data handling (frequency, redundancy, destination) with a simple online GUI.

Stevens’ MEASUREMENTS TO MIND strategy maximizes reliability of your remote monitoring network and makes it simple to connect your station directly to the cloud.


Analog and SDI-12 sensors are connected to the mini sensor module (pictured, larger version also available). eTracker is sensor-agnostic.


Data is automatically forwarded to the cloud for processing, logging, and retrieval, but it’s also stored locally for redundancy on a standard SD memory card.

Data management

Intelligent data management, data buffering, and network verification to ensure successful transmission of critical data.

Cellular connection

Collected data is sent automatically to either Stevens-Connect or forwarded any other destination you specify. Because it’s a 2-way cellular connection, you can send configuration changes back down to eTracker or interact directly with connected SDI-12 sensors.

Simple stations.

Interact with your system and your data from anywhere.

eTracker: Cellular Gateway to the Cloud

Most of our pre-packaged systems are built around eTracker. The reasons? Setup is simple, all configuration and programming is done on the web, you don’t need a data logger, and it works with any analog or SDI-12 sensors. Your data is backed up locally and automatically sent to the cloud-based destination of your choice.

Up to 20x better power efficiency vs. typical cellular modems.

The key to the extreme power efficiency of eTracker is its “hybrid” approach to 2-way communications. Not only does it consume less power than typical cell modems when in standard 2-way communications mode, but it also offers an ultra-low power mode that sacrifices some responsiveness in two-way connectivity for an extremely low power consumption that makes it suitable for remote stations monitoring critical data.


Typical cellular modems

Full 2-way communication mode


Commands can be sent remotely through a web interface to switch eTracker into full 2-way communication mode. When it’s not in full 2-way mode, the command will be received during the next scheduled transmittal of data (each time data is sent from the remote site, eTracker also downloads any new configuration files—the new configuration would contain the command to switch to 2-way mode). In full 2-way mode, the modem is “on-line” and actively listening for commands, and can respond immediately when commands are sent. Power consumption is higher at idle however (150 mA). A new configuration file will also deliver the command to switch back to ultra-low power mode.


Typical cellular modems are always in full 2-way communicate mode, and is always “on-line” and actively listening for commands, responding immediately when commands are sent. Power consumption is always high (220 mA at idle) however, which is why cellular has traditionally not been a practical option for very remote sites that monitor critical data.

Power consumption at idle

150 mA

220 mA

Ultra-low power mode

Power consumption at idle

1.6 mA


Transmit new data

On schedule, or when triggered 

When in ultra low-power mode, new data that is received from an attached data logger or smart sensor is buffered in internal memory and transmitted when:
  1. the next interval of a pre-defined schedule occurs
  2. immediately, if eTracker has been programmed to transmit data when it receives specific data from the attached data logger or smart sensor (this is called “triggered” data). Users also have control over a delay period after the data is received from the logger but before it is transmitted, to account for variable length pauses from different sensors.


Download new configuration data

On schedule, or when triggered 
In ultra-low power mode, each time data is transmitted eTracker will check for a new configuration (that has been created via a web-based interface). Since data is transmitted only when a scheduled interval occurs or if it has been programmed to send when it receives new data (triggered data), new configurations are not able to be downloaded as soon as they are sent.


Web-Based Station Management, Data Access and Data Processing

Use Stevens-Connect to configure your station remotely.

Access all current and historical data from any Internet-connected device, anytime.

Technical Specifications

Key features

Processors 16-bit dsPIC microprocessor, and 16-bit TI MSP430
Data Storage Removable 2 GB SD memory card (FAT 32)
Non-volatile memory All setup parameters
Logging interval 1 second to 24 hours (sensor dependent)
Reporting interval 2 minutes to 24 hours
Cellular antenna External SMA
LED indicators Power, cell network, test message
Cellular communications
  • Dual band CDMA 800, 1900 MHz
  • Penta-Band HSPA+
  • GSM Quad band 850, 900, 1800, 1900 MHz
  • UMTS/HSPA Penta Band 850, 900, 1700, 1900, 2100 MHz
  • EGPRS / WCDMA / HSDPA / HSUPA Protocol Stack

Current consumption

Listen/trigger mode/idle Less than 2 mA
Data receive/store/prepare for transmission 150 mA
Data transmit 250 mA


Input voltage 10 to 18 VDC (reverse polarity protection)
TX output power 24.3 dBm (270 mW)

Performance measurements

Battery and RSSI (signal strength), internal diagnostic log file

Sensor Input

Analog input 4 analog channels, single-ended
Input type: 2 wire, 0 –2.5 V or4 - 20 mA current loop (accessible DIP switch)
Sensor power: 24 VDC switched (under firmware control)
Analog to digital (0-2.5 VDC): 21-bit resolution
Pulse input 4 pulse channels
Input type: Edge triggered
Maximum rate: 4 pulses per second
SDI12 Input Number of sensors: up to 62 sensors
Sensor power: 12 VDC switched, during measurement


Operating temperature -30°C to 65°C (SIM Card selection may limit this range for GSM version)
Storage temperature -40°C to 85°C (SIM Card selection may limit this range for GSM version)
Lightning protection AC transient voltage suppressor (TVS) on each sensor port input


Dimensions (H x L x W) 1 3/8” (3.5 cm) x 5 1/8” (13 cm) x 3 3/4” (9.7 cm)
Weight 10.78 oz (305.6 g)


Cellular antenna SMA
Sensor module interface 30-pin connector


Power cable with flying leads, dipole dual-band cellular 800/1900 MHz antenna.


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