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The ZLog-7 module is specifically designed to measure and record data in high-altitude (near-space) experiments.  A precision sensor measures atmospheric pressure and onboard temperature.  A remote sensor measures outside temperature.  The board will also record battery voltage and GPS data.  All data is recorded on commercially available microSD flash cards and can be download for analysis on a PC.


  • Displays altitude, pressure, temperatures, voltage, humidity, and GPS information in real-time.
  • Tracks maximum altitude – find out how high your experiment reached!
  • Record data for later review onto commercially available microSD or microSDHC flash cards.
  • Dual temperature sensors record both onboard temperature and external temperature.
  • USB PC Interface built-in for configuration and data download/review.
  • Integrated GPS receiver and antenna.
  • Firmware upgradeable.
  • Dimensions
       - 3.62" x 2.21" x 0.38" (92 x 56 x 10 mm) board only
       - 3.78" x 2.36" x 1.10" (96 x 60 x 28 mm) with enclosure
       - 5.43" x 2.36" x 1.10" (134 x 60 x 28 mm) with enclosure and battery
  • Weight
       - ZLog-7 w/ Acrylic and battery holder - 3.5 oz (100 gm)
       - Temp sensor - 0.1 oz (2 gm)
       - Recommended power: Energizer Lithium 9v battery - 1.2 oz (34 gm)
       - ZLog-7 w/ Acrylic, battery holder, battery, cutoff, sensor - 5 oz (141 gm)






Board Layout


Recommended power: Energizer Advanced Lithium 9v  #LA522


Tested to over 12 hours operation under various temperatures ranging from -20C to 20C

Weather balloons in Near Space

Approximately 87000 feet

If your system reports a GPS firmware version earlier than 5759 (look in the Z7-LOG.TXT file on your microSD card) it needs to be updated.  The version is part of this line:

      GPS Firmware Version : AXN_2.31_3339_13082100,5458,PA6H,1.0

Firmware version 5759 can be updated using the following instructions and installer:


Download the manual

Download the Z7 Software Update Loader

Download the latest firmware 2.32 (right-click, save as)

2.32 - for both Rev1 and Rev2

  - add setting UC=1 which displays UTC time with colons inserted.

Download the latest firmware 2.30 (right-click, save as)

2.30 - for both Rev1 and Rev2

  - Fix bug that would, on rare occasion, stop reading the complete startup.txt file or hang while reading.
      - bug was introduced around v2.21, so update is recommended for any 2.2 version firmware.
  - Add option (GN=1) to select GPS lat/lon output in decimal degrees format: DD.dddddd,
     rather than NMEA-0138 format of DDMM.mmmm (GN=0).

Download the firmware 2.28 (right-click, save as)

2.28 - for both Rev1 and Rev2

  - fix setting of inHg pressure units. 

Download firmware 2.24 (right-click, save as)

2.24 - for both Rev1 and Rev2

  - adds caching for GPS log in case of power interruption. 

Download firmware 2.23 (right-click, save as)

2.23 - for both Rev1 and Rev2

  - fix handling of negative GPS altitudes.
  - defaults to option ("GL=2") to log raw GPS data to separate file. 

Download firmware 2.21 (right-click, save as)

2.21 - for both Rev1 and Rev2

  - add option ("LS=n") to set logging interval in seconds (default is 1).
  - add GPS firmware version to system log.
  - add option ("GL=2") to log raw GPS data to separate file.
  - tweaks to read pressure sensor to higher altitude. 

Download firmware 2.0 (right-click, save as)

2.0 - for both Rev1 and Rev2

  - Support for Rev2 hardware.
  - Now uses GPS UTC time for file timestamps.
  - Displays and logs humidity (Rev2 only).
  - Adds system log "z7-log.txt" on the microSD.
  - Improved default settings in case "startup.txt" is missing.

Download the startup.txt file for feet/fahrenheit units (right-click, save as, save to root of your microSD card)

Download the startup.txt file for meters/celsius units (right-click, save as, save to root of your microSD card)

Download Z7toKML.zip - Utility to Convert Z7 .csv file to KML file for loading your flight path to Google Earth

Download ZPlot - Loads the .csv data files that ZLog-7 records.  Makes it very easy to view the data and save .png files for publishing your data.

Save Image produces nicely formatted .png images for publishing your data:



ZLog is designed and assembled in the USA from parts both foreign and domestic.



Hexpert Systems, 2012-2015