SQM-LU : USB connected Sky Quality Meter

Information and software
SQM-LU_Users_manual.pdf Operators manual
  • This manual contains the setup instructions for the unit as well as the communication protocol definition.
UDM for Windows:
Unihedron Device Manager (UDM)

Use this software to:
  • Access the data-logging features of the SQM device attached to your computer.
  • Read version information.
  • Request a reading from the SQM.
  • Read and set calibration data.
  • Read and change the interval reporting settings.
  • Install new firmware.
The operating instructions for UDM are included in the User's manual for the meter.
UDM for Linux:
UDM for Mac OS X
  • Open dmg file.
  • Then drag app to the /Applications directory.
UDM: source code
Programming langauge: Lazarus/Freepascal

Windows USB driver
Max OS X USB driver
USB driver
  • The latest USB drivers can be found at FTDIChip
  • Special tips if Mac does not connect to USB meters: DEXT Driver Install for Monterey/Ventura PDF
  • Recent Linux distributions come with the FTDI VCP driver installed.
Firmware files Firmware updates
  • These firmware files are to be used by UDM (see above).
  • See the operators manual for firmware revision history.
Sqm3Setup.exe SQM-Reader by Knightware 
  • Windows software by Knightware to read SQM-LE/LU/LR/DL devices.
  • Check www.knightware.biz for latest version as well as SQM-Reader-Pro which has many more features.

Software examples/utilities
Perl script to read and log SQM-LU data.
Perl script to read and log SQM-LU data. See file contents for installation details.
Py3SQM Py3SQM (Python 3 (PySQM) is a multi-platform, open-source software designed to read and plot data from Unihedron SQM-LE and SQM-LU photometers, giving as an output files with the International Dark Sky Association (IDA) NSBM Community Standards for Reporting Skyglow Observations.
RPi with PySQM Implementation of PySQM on a Raspberry Pi Single Board Computer by Ruben Diez Lazaro.
readsqmlu.py Reads a value from the SQM-LU.
add_pos.py Adds position information to all .dat files in a directory
SQMroid SQMroid reads and logs SQM-LU data using an Android phone for a very small fee. Requires a USB OTG.
SQMDroid Android program to read SQM-LU data. PDF here , apk here

INDI Driver
The SQM-LE is officially supported in INDI and users who capture images using any of INDI clients (such as Ekos or PixInsight) will get the MPSAS value in the FITS header. Discussion forum.