Recent Posts

Pages: 1 ... 8 9 [10]
General Discussion / Turtle studies
« Last post by admin on October 24, 2012, 07:42:21 pm »
Some researchers have used the SQM light meters for studying the effects of artificial lighting on sea turtle habits.

A few points about such studies would be:
  • The Field of View (FOV) may be critical in your tests, see this chart. If you are using the meter as a directional light meter then the SQM-L model would be the best suited to pointing at specific bright spots.
  • If you are taking sample readings over a period of time for comparison, make sure that the meter is located at the same spot and facing the same direction each time. It may be a good idea to have a registration stand (peg in the ground with a holder for the meter) to ensure that the meter is always facing the same direction for each successive sample.
  • Also be aware that the FOV will capture obstructions like your body, so be sure to always hold the meter in the exact same direction above your head (to avoid and shading or reflection from your body into the meter sensor).
  • You may want to gather readings from both Zenith (straight up) and various angles towards and away from the shore vertically and horizontally to get an idea of what the Turtles would see in their travels.
  • Make sure you record the time and date as the Moon will heavily influence sky brightness. Even if the night is very overcast, a moonlit night will provide a wide range if readings. You will get the most consistent readings on moonless nights.
  • If you have the funds, and access to a secure site on the beach, you may want to consider the SQM-LU-DL which can sit unattended for months collecting readings for later retrieval.
  • The meter will likely not saturate at all in the night, even if you point it directly at distant condominium or hotel lighting.
  • Please see this report (by Pierantonio Cinzano) for spectral response of the meter and other scientific details.
  • A longterm exposure photo of the beach-line may be a good base image to obtain relative brightnesses so that light readings can be noted on there.

Here are some resources:
Please reply with your comments regarding details about your own studies or questions.
General Discussion / Notifications
« Last post by admin on October 23, 2012, 05:30:02 pm »
Since many members have come from the mailing list where all messages went to all members, you may like getting emails on every single posting to this forum. This can now be done by going to Profile->Modify_Profile->Notifications

Ensure the following is set:

  "For topics and boards I've requested notification on, notify me: Instantly"

As shown here:

You must also select "Notify" on each board. For example in the "General Disscussion category" board, there is a "Notify" button near the top right side:

This is a new setting being tested (Board Notification Mod), hopefully it works well.
SQM-LU / Extending the USB cable
« Last post by admin on October 23, 2012, 03:47:59 am »
The SQM-LU and SQM-LU-DL come with a standard 15ft (5m) cable which is the design limit for a standard USB connection.

A USB cable extender may be used if you require a longer connection.

We have successfully used the IOGEAR GUCE62 which uses an Ethernet cable (Cat5e, or Cat6) to achieve up to a 164' extension:

* One customer reported problems with a different model (GUCE51), so we now recommend the above GUCE62 which comes with a power  supply (not shown).
SQM & SQM-L Handheld light meters / Battery connection
« Last post by admin on October 23, 2012, 01:36:43 am »
If the meter does not start despite having a fresh battery, the cause may be a loose battery clip.

Using pliers, lightly squeeze the 6 petals around the flower-shaped connector as shown in the image below:

Dear all,

1) I am very glad to learn about this new forum on the same day that I started to write a series of posts on my blog, under the title of " brief history of participatory night sky monitoring from Italy".

2) the posts will be available in Italian and English, and here is a preface: (ENGLISH) (ITALIAN)

3) I hope this will be of interest to forum readers, as a minimum as a quite composit case history of Unihedron products, even though -based on feedback we had in the past, I am quit sure some of you will appreciate more than just the sensor technology side of the story proposed in the blog.

thank you for your attention, and regards

Andrea Giacomelli (aka pibinko)

DISCLAIMER: the blogs posts on the "brief history of participatory night sky monitoring from Italy" are freely inspired from the BuioMetria Partecipativa project (, of which I am one of the creators.
However the BSDBPM blog posts will not represent an official position of the project...while this is evolving steadily, I saw the value of also providing a more personal view on some of the episodes we have been living and working through. Please refer to or to for the BuioMetria Partecipativa project itself.
General Discussion / Choosing a Unihedron dark sky light meter
« Last post by admin on October 22, 2012, 01:31:13 pm »
Unihedron offers the following variations on the dark sky light meter categorized into hand-held or connected models.

Hand-held meters:
The best choice for casual astronomy or environmental dark sky measurements is the SQM-L. It is a hand-held model that provides a quick reading. The narrow field of view (~20°) is suitable for urban and rural settings.

The SQM has a wide field of response (~42°) which is more suited for rural use where trees or streetlights are not directly in the field of view.

Connected meters:
If you want the readings sent directly to a computer, but not instantly readable in your hand, then one of the connected models is a better choice. Software running on a computer must be used to read and/or record the light value from the meter. All connected meters use the narrow field of view like the SQM-L, and custom orders can be made to remove the lens if necessary.

The SQM-LU (USB) connects with a 15ft (3m) USB cable to a computer.  A cable extender could be used to obtain a 198ft extension.

The SQM-LE (Ethernet) connects to either a computer or network router with an Ethernet cable and must also be powered separately (AC adapter included). The readings can also be directly read over the Internet.

The SQM-LU-DL can be powered by an external battery pack (included) and take readings autonomously over extended periods. This model is suitable for gathering unattended readings from a remote site. The readings can be downloaded to a computer later with the supplied USB cable.

The SQM-LR (RS232) connects to a computer with an RS232 cable (6ft is supplied, 300 ft max) and must also be powered separately (AC adapter included). This is useful for computers or modems that have an RS232 connection.

FOV (Field of view): The field of view is not a sharp edged cone, there is some drop off as shown here: FOV curves. The value reported is the Full Width Half Maximum (FWHM)
Weatherproofing / Drainage
« Last post by admin on October 21, 2012, 11:30:40 pm »

It is important that the bottom of the weatherproof housing must have a drainage hole.
This housing is not hermetically sealed, so any moisture that builds up inside can remain trapped unless the bottom of the housing has a clear hole.
The Unihedron housing does have a hole at the bottom, and the included open-cell foam insert prevents bugs from entering while allowing water to drain.
SQM-LU-DL (Datalogging light meter) / Warped lensplate
« Last post by admin on October 21, 2012, 11:23:29 pm »
Some older DL units may have experienced a warped plastic lensplate when sitting in the hot Sun for extended periods of time. The exact reason is being investigated by our plastic supplier. We are working to get a glass lensplate for the DL model within the next few months.

Currently the good plastic lensplate for the DL model has a vertical seam near the right side. If your lensplate is solid, then it needs to be replaced, please contact us to arrange for a repair.

SQM-LU-DL (Datalogging light meter) / Real Time Clock slow or stopped
« Last post by admin on October 21, 2012, 11:16:01 pm »
Some older units of the SQM-LU-DL may have experienced a slow or stopped RTC (Real Time Clock). It has been discovered that one part on those earlier boards could absorb moisture over time, and short out the oscillator. If you have noticed this behaviour, please contact us to arrange for a repair.
Connected meters (SQM-LE/LU/LR/DL) / UDM updates
« Last post by admin on October 21, 2012, 11:11:40 pm »
A recent version of the UDM (Unihedron Decvice Manager) is available here:

The changelog is: (20150924)
 - local timezone region and name drop down combo boxes made read only
   to prevent user from entering invalid descriptions causing
   "Error! IORESULT: 0" during retrieve all records. (20150910)
 - Header elevation had decimal value, now integer.
 - Header definitions now opens PDF as well as going IDA link. (20150815)
 - Allow setting SQM-LE XPort defaults button when single click on Found Erthernet device. (20150814)
 - Vector model: remove dual v2x v1x accell/mag requests from log continuous mode. (20150813)
 - Vector model:
   - remove ""0.0" is not a valid float" error for decimal=comma regions (like Europe).
   - DL Retrieve All corrected CSV heading of Ax, Ay, Ax to Ax, Ay, Az
   - plot Show data dialog cancels properly on unselected file.
   - plot ShowLines toggle fixed.
   - plot Legend range adjustable by entering min/max values.
   - disabled export image button since it only exports the plot (not the legend).
   - reorganized plot controls. (20150707)
 - DL retrieve now logs the time difference which is helpful for interpreting long data logs that need more accurate timestamps.
 - RS232 firmware update is properly enabled aftre LR model has been identified. (20150608)
 - DL time difference display (datalogging tab) now shows "slow/fast" indication instead of just absolute time difference.
 - Vector calibration ignores magnetic spikes (from lighting ballast etc.).
 - Vector model: header contains calibration information.
 - Vector model: Plot now properly ignores header calibration information. (20150603)
 - Vector model: Log Continuous mode logs raw Accelerometer and magnetometer values
 - Vector model: Log Continuous mode and DL Retrieve mode logs Zenith degrees (as well as Altitude) per SDF_1.0 format. (20150531)
 - Trap exceptions for places where sun does not rise/set to prevent error during log cont. mode when location is defined. (20150514)
 - invert Vector plot legend (bright 10mpsas at top, dark 22mpsas at bottom) (20150508)
 - fix: Comm Terminal auto scroll windows
 - Add range settings to DL retrieve page. (20150505)
  - Bugfix: reading button reading least significant digit was zero from version since version
  - Feature: Show Instrument_ID from header description on "Found devices" listing.
  - Bugfix: Warn if timezone header settings contain spaces.
  - Allow DL retrieve window to slected from Tools menu if no DL is attached.
  - Fix vector data loading in Windows.
  - fix spelling mistake (Azimuth) in Vector log header screscription.
  - DL header "number of lines"; remove unnecessary "+" at end which was added a while ago.
  - Show logs directory in View:Directories dialog
  - Allow doublclick in multidevice found window to immediately get reading.
  - Reading button now properly shows negative signed temperatures instead of 0.0C
  - Added ethernet "XPort defaults" error checking for non-existent or slow telnet server.
 - add simulation-from-csv-file feature.
 - Remove Vector plot tab from Retrieve page for all other models.
 - ADA factor tab selected automatically on log cont page.
 - Configuration page shows temperature alarm in colour now.
 - Logcont trigger control radio button text contains integer spinwheel
 - Vector: Add vibration count to retrieve all function.
 - LogCont chart dots now obey trigger settings, not every 1 second.
 - Logcont left legend marks formatted at 2 decimal places now (#.##)
 - Plot line thickness enlarged from 1 pixel to 2 pixels for better readability
 - Log continuous page changes to make larger chart tab and move trigger to separate tab shown on startup.
 - Clean up results windows after loading firmware
 - LR port select added /dev/ttyS* options and sorts entries
 - Minor improvements to DL screen
 - Generic vector model updates
 - Configuration tab: resize calibration data window to fit larger dataset
 - DL auto identify various EEPROM FLASH sizes
 - simple plot of points added to log continuous page
 - remove extra LM#x that sets DL mode every time Datalogging tab is selected
 - added two view->log messages to identify the command line and configpath
 - firmware files show proper date, and old ones have been moved to archives sub-directory
 - added some command line options for auto logging
 - changes from the configuration page no longer trigger device reads
 - vector model added
 - USB-find troubleshooting info added to log 2014-02-26
 - rotstage set to full steps (50 steps per 90 degrees) 2014-02-16
 - remove auto communication to get calibration and device info when device is initially selected
 - add GDM feedback buttons to log continuously screen 2014-01-23
 - Add rotational stage 'rotstage' control 2014-01-13
 - Add: Tool to convert old style csv files to new sttyle dat files.
 - ADA (non-SQM) device logging 2013-12-21
  - Add: Tool to add Moon data to .dat files and output .csv file for spreadsheet 2013-11-20
  - Fix: DL logfile fix for missing European floating point records caused from last two changes. 2013-11-20
  - Fix: DL logfile positive temperatures missing from last change. 2013-11-17
  - Fix: DL logfile negative temperatures cropped decimal place. 2013-11-11
  - change decimal separator from international to decimal point for compatibility to header spec 2013-11-10
  - LR model: added /dev/ttyUSB* defaults for Linux
  - Timezone for DL removed from DAT records for compatibility to header spec 2013-10-07
  - Timezone for DL retrieve fixed, and listed in DAT records.
  - CRLF properly logged in .dat files according to header specification.
  - Window can be resized so that more found devices are shown without scrolling.
  - Option for finding USB or Ethernet devices only from file menu. 2013-07-23
  - Added synchronous and persistent options to log-continuous hotkey-annotations. 2013-07-19
  - Fix Mac Enter on DL trigger values causes Find button to be pressed. 2013-06-22
  - Fixed up hotkey annotation to allow for more specific hotkeys (like numpad keys) 2013-06-19
  Added annotation and hotkeys to Log-continuous mode.
  Fix Linux non-identification of some USB FTDI devices because of driver naming.
  Added "Records Missed Count" to log continuous mode for easier troubleshooting of faulty devices/connections. 2013-05-18
  Fix DL tab read unit time bug when extra CRs are received
  Add DL battery estimator records indicator, and 60 minutes calculation fix, and custom mAH rating works now.
  XPort default button is only enabled when an Ethernet device is selected.
  Configuration page details (including version information) are refreshed with; refresh-button, tab-click, and selected unit change.
  USB discovery on Linux machine is now (because udevadm requires root access): ls -al /dev/serial/by-id/
  Added "every minute on the minute" log continuous setting.
  Fine control of log-continuous per-second recording. No more drift, each record request initiated on the 1-second boundary. 2013-02-01
  Add RS232 connection ability
  Changeable logs directory re-implemented
  Log continuous button on main info tab with settings similar to DL logging.
  Add link to DL header online definitions to DL Header window. 2013-01-09
  Fix DL retrieve all voltage and mpsas in European number format was 0.
  Fix Mac DL configuration file location directory creation. 2012-12-22
 Cosmetic: Label units on Report Interval tab.
 Information tab buttons for Header and Log-on disabled when no unit is selected.
 Increase timeout for responses (from 1 to 3 seconds) in case OS is a bit slow. The symptom was that results in some logfile records were missed. 2012-12-16
 Add single record log button to information tab
 Update DL log filename according to new datalog header standard (.dat extension, Intrument ID name, stored in log directory) 2012-11-13
 Linux USB identification now ignores non-FTDI serial port devices.
 Added splash screen to identify that devices are being searched.
 Linux USB error-check for user added to dialout group.
 Fix: DL clock display was too tiny on Linux, sometimes blanked out. 2012-10-31
 DL: Fix; Read log temperature parsing was sometimes 0.0
 Windows: removed debug writeln causing crash after I/O error
 Mac version updated for new DL data header   2012-10-27
 DL: Fix; Read log record by parsing commas instead of fixed field where  negative mpsas might occur.   2012-10-21
 Background colour of non-editable field changed to default because some themes show this as black background.
 Added Help->VersionInfo menu item. Displays changelog.txt.
 Added Firmware Info button. Displays fchanges.txt.   2012-10-15
 Minor changes to new data format.
 Added fix for SQM-LE Xport data defaults (00:02 disconnect time).
 Battery calculator default to Alkaline (as supplied with order, not optional Lithium)
 Fix: DL result window was blank if DL mpsas record had extra negative sign character. 2012-10-04
 Added new DL data format (for testing) defined by Chris Kyba and associates.
 Added directory location definitions (Linux, Windows) for:
  - saving temporary data and
  - loading firmware files
  - accessing the time zone database
Pages: 1 ... 8 9 [10]