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Camera Troubleshooting

Points of failure

In order for proper operation of the DFN observatory a few things need to happen:

  • The observatory box must be powered - LED indicator are lit (at least on the micro controller PCB)
  • The embedded PC must boot successfully - how to troubleshoot
  • PC has to tell micro controller to power on
  • DSLR has to power on
  • PC has to tell microcontroller to start taking images
  • Microcontroller has to trigger camera through optocoupler and shutter cable
  • DSLR has to be configured properly to take photos via gPhoto2 over USB
  • DSLR has to take photos - how to fix
  • LC shutter has to flicker - investigate LC shutter malfunction

Initial Steps

The first task is to figure out what's not working, starting with the most likely and easiest to check steps. If that doesn't work then we can move on to the trickier steps later.

Are the drives full? Try df -h to see how full they are. This will list a percentage full for all partitions (but not the external drives if they aren't powered on and mounted).

Simple check the camera system on remote site, reboot


Check the camera system status

Open the enclosure door - there is often a key hanging somewhere on the camera stand. Or use long nose pliers. Inspect LED lights - Are any of them lit?

If not, the problem might be in power. For mains powered sites, check power cable, circuit breaker etc. If you have a voltmeter/multimeter, disconnect the screw-in DC power cable from the bottom of the camera system enclosure and check voltage - it should read ~ 12V.

If some indicators are lit, take a photo and e-mail it to us if unsure what to expect.

TODO: add photo of DFNSMALL camera system inside

Reset the camera

Cycle the power of whole camera system.

There is a DC power cable connected to the bottom of the camera box - as shown on the photo
DFN camera DC power cable connection
. It is the biggest connector, and it needs to be unscrewed before unplugging. Once the power is disconnected, please wait for about 1 minute and then connect it back, tightening it again. Shortly after re-connecting the power, there should be a sound of a fan inside the box and a little later a short beep sound like when PC is booting, and the fan should go silent.

DFNEXT system

Check the camera system status

The DFNEXT type of camera system has built-in WiFi, which is in most cases configured to serve as an access point. That means, providing the system is running, there is network DFNEXT0XX (XX depending on the unit serial number). One can see this network with a phone, tablet or laptop.

If the WiFi network is detected, but the camera system is not communicating remotely over the Internet, the best thing is to initiate a reset in a web interface over WiFi.

Software reboot

Connect to the WiFi network and then open the Web GUI interface and reboot the system.

Hard reset - cycling the power

If the WiFi network was not visible or the web interface reset was not working, the other option is to power cycle the whole camera system.

There is a DC power cable connected to the bottom of the camera box - as shown on the photo. It is the biggest connector, and it needs to be unscrewed before unplugging. Once the power is disconnected, please wait for about 1 minute and then connect it back, tightening it again. Shortly after re-connecting the power, there should be a sound of a fan inside the box and a little later a short beep sound like when PC is booting, and the fan should go silent.

How to troubleshoot PC booting

  1. Power on the observatory box and try to locally connect with ethernet cable or WiFi (if the box is is equipped with it, eg DFNEXT type)
    • for wired connection, make sure you using the correct ethernet port for laptop connection. (Better try both if unsure.)
    • make sure the WiFi antenna is attached if you want to use WiFi - the white little stick on the bottom of the DFNEXT box.
    • remember it may take a few minutes to boot the camera OS since powering it on
    • for WiFi, the observatory is by default configured as an access point (2.4GHz 802.11g), with SSID same as the observatory host name, eg DFNEXT014 - try scanning for this SSID.
    • you can try to ping the corresponding IP address first before ssh connection - for wired
    or for WiFi
  2. If the previous step fails:
    It is possible that the filesystem got corrupted and the booting process is stuck at filesystem check & repair. That can happen if the observatory system was earlier powered off (unplugged) without shutting down the OS properly. In that case, user keyboard interaction is required, so you will need to:
    • connect USB keyboard
    • connect monitor (HDMI works with all cameras, some DFNSMALLs support also VGA)
      please note that the monitor in most cases must be plugged in before powering on the camera. If the camera is already powered, connect the keyboard and monitor, hit Ctrl+Alt+Delete at least seven times and wait for the box to reboot. Only if that is not working, power off and power on the box to enforce reboot
    • follow the instructions you will see on the screen
      root password will be required, then it is mostly hitting 'y' key
  3. If the rest of the system in the box seems to be working/powered, just the PC has no signs of life, check it is powered:
    • The power connector on the PC board may have bad connection.
    • In case of DFNSMALLs, there is either Advantech PC (black heatsink) or Commell LE-37D PC (small silver heatsink). The Advantech PC has a round DC power connector, which is prone to bad contact. Try to wiggle with is a bit, push it deeper. That often helps. On the other hand, the white plastic Molex connector of Commell LE-37D PC is very reliable.
    • In case of DFNEXTs, there is a screw terminal, where the screws can loosen while working on something else inside the camera enclosure or during transport. This is easy to fix by tightening the screws, just make sure the wires are well pushed into the terminal. It is also very easy to check the voltage on the terminal with multimeter - it should read approx. 12V DC.

DSLR is not taking photos

power on the DSLR (or stop interval control service if running)

run command "lsusb", should list device like

Bus 002 Device 004: ID 04b0:0436 Nikon Corp. 

if not, visit te site and check the wiring - USB data cable and power cable to the DSLR

Test if DSLR can capture images

if listed, run command "gphoto2 --capture-image-and-download"

Samyang lens apperture ring not set correctly

if you get response

root@DFNEXT077:/data0/latest# gphoto2 --get-config /main/capturesettings/f-number
Label: F-Number                                                                
Current: f/655.35
Choice: 0 f/655.35

root@DFNEXT077:/data0/latest# gphoto2 --capture-image
*** Error ***              
*** Error ***              
Camera Mode Not Adjust FNumber
ERROR: Could not capture image.
ERROR: Could not capture.

that means the Aperture ring of the Samyang lens is in wrong position.

Set it to F/22 (which printed in red)


  • Photos have to be downloaded to the PC via gPhoto2 over USB
  • Photos have to be stored in /data0 and renamed properly by the DFN's capture control software
  • Photos have to be copied over to /data1, /data2 or /data3 by the data move script

DSLR memory card is full, download the images manually

This situation may occur for example when the regular interval capture during night is interrupted (power loss, operator SW stop) or when all the disks are full and no room is left to download images from the DSLR internal storage.

The software will eventually cope with that (whatever images found on the memory card DSLR are automatically downloaded at the beginning of regular run in the evening. However, there may be situations when one wants to put the files into specific directory - this section describes how to do it manually or semi manually.

Check if DSLR memory card has any data on it by

 gphoto2 -L -R

Long list of files means it may be full.

A very useful diagnostic command is

 gphoto2 --summary

which (togethher with heaps of other info) prints the usage and free space on the memory card:

 Storage Devices Summary:
       StorageDescription: None
       VolumeLabel:  [Slot 2]
       Storage Type: Removable RAM (memory card)
       Filesystemtype: Digital Camera Layout (DCIM)
       Access Capability: Read Only with Object deletion
       Maximum Capability: 64014417920 (61048 MB)
       Free Space (Bytes): 60096512 (57 MB)
       Free Space (Images): 0

This makes it clear the card is full.

To manually download the images and free up the card, there are two options:

1) Direct gphoto2 commands: 'gphoto2 -P -R' to download, followed by delete 'ghoto2 -D -R' - then you can drop the images to the corresponding (yesterday's or whatever) directory where they belong.

2) May be better and easier is to run interval control test /opt/dfn-software/, that does everything like regular interval control run at night, but it forces ~ 5 minutes test run regardless the time of the day. Interval control test creates a new directory wgere it dumps all the images on card in the beginning plus the few taken during the short run.

DSLR memory card file sytem is corrupted or card damaged

Cannot delete images from card

The memory card problem can demonstrate by failing delete of all images from the card after download. The Interval capture control SW uses the following gphoto2 command internally and it is possible to run it manually to troubleshoot the problem - which otherwise may demonstrate as missing images from later part of the night.

more than to directories with images listed
gphoto2 --delete-all-files -R

or equivalent shorted

gphoto2 -D -R

in case of memory card FS problem we get

*** Error ***              
PTP Device Busy
*** Error (-110: 'I/O in progress') ***       

and the deleting fails.

Also two or more directories with images listed by

gphoto2 -L -R
There is no file in folder '/'.                                                
There is no file in folder '/store_00020001'.
There is no file in folder '/store_00020001/DCIM'.
There are 999 files in folder '/store_00020001/DCIM/139ND810'.
#1     DSC_0042.NEF               rd 45431 KB application/x-unknown
#2     DSC_0043.NEF               rd 45458 KB application/x-unknown
#3     DSC_0044.NEF               rd 44759 KB application/x-unknown
#997   DSC_1038.NEF               rd 39808 KB application/x-unknown
#998   DSC_1039.NEF               rd 39851 KB application/x-unknown
#999   DSC_1040.NEF               rd 39710 KB application/x-unknown
There is no file in folder '/store_00020001/DCIM/140ND810'.
There is no file in folder '/store_00020001/DCIM/141ND810'.
There are 519 files in folder '/store_00020001/DCIM/142ND810'.
#1000  DSC_1041.NEF
#1001  DSC_1042.NEF               rd 39875 KB application/x-unknown
#1002  DSC_1043.NEF               rd 39764 KB application/x-unknown

To fix this, format the memory card. If the problem repeats, replace the memory card and/or make sure the USB3 cable between the DSLR and PC is in a good shape and not causing errors (syslog inspection should reveal that if physical cable does not look damaged or sharp bent).

Solar Power

Morning Star Sun Saver charging controller

User manual - at manufacturer's web

User manual - at Battery Stuff web

Status LED Error Indications

Solar overload Flashing Red
High Voltage Disconnect Flashing Red
High Temperature Disconnect Flashing Red
Damaged local temp. sensor Solid Red (1)
Damaged heatsink temp. sensor Solid Red (1)
Damaged input MOSFETs Solid Red (1)
Firmware Error Solid Red (1)

(1) - A heartbeat indication flickers the Status LED off briefly every 5 seconds. A solid red Status LED indicates that a critical fault has been detected. Critical faults typically indicate that the controller is damaged and requires service.

Battery Status LED Error Indications

High Voltage Disconnect R - G Sequencing
High Temperature Disconnect R - Y Sequencing
External Wiring Error R&G - Y Sequencing
Load Overcurrent R&G - Y Sequencing
Load Short Circuit R&G - Y Sequencing
Self-test Error R - Y - G Sequencing


LED error indications can be interpreted as follows: “R - G sequencing” means that the Red LED is on, then the Green LED is on, then Red LED is on....

“R&G - Y sequencing” means that both the Red LED and Green LED are on, then just the Yellow LED is on, then Red and Green LED are on....

Common Problems

Problem: No LED indications

Solution: With a multi-meter, check the voltage at the Battery terminals on the SunSaver and the Solar terminals on the SunSaver. The solar module must be in good sun and battery voltage must be at least 1 V to power the SunSaver and activate the dead battery charging function. Problem: The SunSaver is not charging the battery. Solution: If the Status LED is solid or flashing red, see Error Indications. If the Status LED is off, measure the voltage across the Solar input terminals of the SunSaver. Input voltage must be greater than battery voltage. Check fuses and solar wiring connections. The solar module must in full natural sunlight.

Problem: No load output.

Solution: If the battery status indication is Solid Red, the SunSaver is in the Low Voltage Disconnect (LVD) condition. The load will automatically switch on when the battery recharges to the Low Voltage Reconnect (LVR) threshold voltage. See the specifications in section 7.0 for LVD & LVR settings.

NOTE: If the SunSaver model is SS-6-12V or SS-10-12V (no load control feature), the controller may be damaged.