Flextrak is a PiZero form factor AVR based High Altitude Balloon Tracker.

This board has a GPS receiver and radio transmitter designed for tracking high altitude balloon flights utilising a Raspberry Pi Zero W. An optional APRS board/cut down board will be available soon.

You will get :

  • FlexTrak Board
  • Battery holder + clip
  • 4 x 11mm Standoffs with screws to attach to the Pi+
  • Standard non stacking low profile header
  • RG174 Tail for making into an antenna see this article.
  • Pi Zero W Board with Camera Cable (Camera not supplied - please order separately)
  • 32Gb SD Card preloaded with FlexTrak code.

The board is supplied with a 434/868 or 915 MHz LoRa radio transmitter   To track the location of flight you also need a suitable radio receiver, aerial and PC on the ground.  To can be tracked with a mobile phone connected to our LoRaGo device.

It features:

  • Efficient built-in power regulator providing run time of over 20 hours from 4 Energizer Lithium Ultimate AA cells
  • Highly sensitive UBlox GPS receiver suitable for altitudes up to 50km
  • Temperature sensor
  • Battery voltage monitoring
  • Allows use of Raspberry Pi camera
  • Mounting holes and spacers for a solid connection to the Pi
  • Tracker will continue to work even if the Raspberry Pi fails. 

The open-source software provides these features:

  • Radio telemetry with GPS and sensor data using UKHAS standard
  • Radio image download using SSDV standard
  • Multi-threaded to maximize use of the radio bandwidth
  • Variable image size according to altitude
  • Stores full-definition images as well as smaller transmitted images
  • Automatically chooses better images for download
  • Supplied as github repository with instruction
  • Optional APRS transmission with additional hardware.
  • Optional external temperature probe (Available soon)

Weight Breakdown:

Flextrak Board          -  16g

Header + Standoffs  -  14g
Battery Holder+Clip     -  13g
PiZeroW + Cable          -    14g


Not supplied for information only:
Energizer L91 Lithium (AA)  - 14.5g x 4


Instruction Manual: https://store.uputronics.com/files/FlexTrak_Manual.pdf




Flextrak Raspberry Pi Kit

  • Brand: Uputronics
  • Product Code: HAB-FLEXTRAK
  • Availability: 51
  • £216.00

  • Ex Tax: £180.00

Available Options


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Tags: Pi In the Sky Kit