Freematics ONE is an Arduino compatible vehicle telematics prototyping platform, in form of a OBD-II dongle which plugs into a vehicle’s OBD-II port, with ATmega328 (same as Arduino UNO) as main controller having access to vehicle ECU, GPS, 9-DOF motion sensor and possibly external sensors. Freematics ONE is easy as Arduino to get started with right from Arduino IDE with dedicated Arduino library and example sketches.


  • Based on original OBD-II solution from Freematics OBD-II Adapters
  • Programmable as Arduino UNO from standard Arduino IDE
  • Access to all standard OBD-II PIDs, DTC, VIN from vehicle ECU
  • Measuring G-force, motion and orientation
  • Measuring car battery voltage
  • Pinouts for digital and analog I/O
  • Data storage on microSD card up to 32GB
  • GPS/GLONASS geolocation (with external GPS receiver)
  • BLE transparent serial communication (with optional BLE module)
  • Low power mode @10mA
  • Working out-of-box as OBD/GPS/motion data logger (on microSD card)



  • ATmega328p main controller
  • STM32 based OBD-II solution (CAN BUS, K-line, NMEA parsing)
  • MPU-9250 MEMS motion sensor
  • CC2541 BLE transparent serial module (optional)
  • Self-popping microSD slot
  • xBee socket for optional cellular module
  • Enclosure dimensions: 60x48x20mm

Physical Interfaces

  • OBD-II male connector
  • microUSB port
  • microSD card slot
  • I/O socket (for external GNSS receiver)
  • xBee socket

OBD-II Compatibility

Freematics ONE plugs into the OBD port usually located under the steering column. To check if your vehicle is OBD-II certified, open your hood and find the sticker that looks like this:


Vehicles using following vehicle protocols are supported.

  • CAN 500Kbps/29bit
  • CAN 500Kbps/11bit
  • CAN 250Kbps/29bit
  • CAN 250Kbps/11bit
  • KWP2000 Fast
  • KWP2000 5Kbps


Freematics ONE supports geo-location positioning by external GPS receiver. GPS receiver is connected to Freematics ONE’s I/O socket by Molex connector.

UBX-M8030 GPS Receiver with Molex connector Freematics ONE GPS Connector F-ONE_3497



Freematics ONE has a microSD slot under the side cover. The card reader is connected to ATmega328p through SPI. Standard Arduino SD library is used for microSD card access.

Cellular Module

Freematics ONE has an xBee socket onboard which provides the possibility to extend its cellular network communication capability.Currently SIM5360 (3G WCDMA) and SIM800 (2G GPRS) modules are two available options.

BLE Module

Freematics ONE has an optional embedded BLE module (TI CC2541) which allows transparent serial data communication over BLE.

Low-Power Mode

Freematics enters and leaves low power mode programmatically. In low power mode with all peripherals (GPS, GSM, WIFI) powered off, the power consumption is around 10mA. This prevents car battery from going flat while the main controller is still able to run code and perform low-power tasks like motion detection by MEMS sensor.

PCB Layout

Following is the PCB layout of Freematics ONE. The schematic is here. We supply head-less (without OBD-II male connector) version. Please contact for details.

External I/O

Two I/O pins of the ATmega328P (PC0, PC1 or A0, A1 in Arduino context) are led out to at one corner of PCB. They can be used for digital I/O and analog input.

The I/O socket can also be used for digital I/O (3.3V) in the new revision (2021) with newly added API.


An Arduino sketch can be uploaded to Freematics ONE exactly the same way as for an Arduino UNO from standard Arduino IDE through USB port. Please refer to the Users Guide for more related information.

Pre-loaded Firmware

Datalogger sketch is pre-loaded before shipping, your Freematics ONE will work out-of-box as a vehicle data logger which performs following tasks:

  • Connecting to vehicle via OBD-II port
  • Connecting to GPS receiver (if available)
  • Creating a new file on microSD card
  • Logging OBD-II, GPS, MEMS sensor data to the file (file format)

Shipping List

  • Freematics ONE x 1
  • Micro USB cable x 1
  • Wireless module x 1 (optional, plugged-in)
  • GPS Receiver x 1 (optional)


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