HEM Data Products

Real-time CAN Mini Streamer™


J1939 Mini Streamer™

The OBD Mini Streamer™ transfers OBD, CAN and J1939 data from a car or heavy duty vehicle to a mobile device (tablet, smart phone or PC) in real-time. Data is transferred using WiFi, so the technician can be in or outside of the vehicle.

The Mini Streamer is valuable for the service technician, vehicle inspector, or engineer who wants to view data in real-time for immediate feedback. It is also valuable to determine vehicle performance on a dynamometer.

The user has the option to send data to a website for review and analysis. Example DAWN Dashboards are at http://dashboard.hemdata.com/.

The Mini Streamer can simultaneously send and receive three types of messages:

  • Generic OBD-II – standard on all cars and light trucks after 1996 (mode $01) as defined by J1979
  • Enhanced OBD – similar to a service scan tool database; specific to each OEM (mode $21 and $22)
  • CAN messages – These include 11-bit, 29-bit, J1939 and CANOpen

The streamer can also transmit GPS data.

J1939 Mini Streamer Specifications

ISO 15765-4 (CAN, 11-/29-bit, 250/500/1000 kbps) Yes
J1939 Yes
J1708 Yes

No. of Protocol Ports (Channels)

3 CAN Channels (Auto-detects baud rate)

Real-time PC data


RT Connections to PC


LEDs for status


Operating system

Proprietary RTOS

GPS (NMEA 0183)



Size (inches)

Size (mm)

Weight (g)

J1939 Connector:  1.5 x 1.5 x 1.0

40.1 x 40.1 x 29.1


Supply Current:

80 mA. Up to 200mA with WiFi

Operating Temperature C

-40 to +110

Operating voltage

4 to 30V

Over/Under Voltage protection

-30 to +100V


1 Year


HEM Data DawnPlot™ and DAWN MessageMonitor™ work with the Mini Streamer for real-time data and the Mini Logger for stored data.

  • Use DawnPlot™ to plot engineering values in real-time on a PC or iPhone/iPad. Features include cursors, drag zooming, multiple y-axis overplots, and histograms.
  • Use DAWN MessageMonitor™ to monitor, summarize, and display network traffic in real-time with a PC or iPhone/iPad. Message Monitor has many analysis features, such as sorting, filtering, and plotting specific bytes within messages.

HEM Data creates custom applications. HEM Data will quote a custom app upon request or we can assist the user in developing one.

DawnEdit™ provides the OBD-II and J1939 databases relating parameters to messages. DAWN MessageMonitor™ will help you develop more advanced databases. Using the two software packages together provides an efficient way to reverse engineer messages and to then summarize your results in a standard DawnEdit database.

Reasons to use Message Monitor:
• Reverse engineering
• Understand broadcasted messages
• Determine message update rate
• Debug the Controllers on the Network
• Understand how to initiate Enhanced OBD Diagnostic Session
• Any application where messages are the focus

DawnPlot and MessageMonitor are both available for iPhone/iPad. Also, HEM Data creates custom applications for iOS, Android and Windows.


Custom DawnPlot iPad App

J1939 Mini Logger™ OBD Mini Logger™ DAWN Telematics™ DAWN™ Software ADAQ Mini™ DAWN Dashboard™