Sony LANc Control with SMI file export

The Sony LANc control is similar to RS232, except it's inverted and has a long stop bit. A very good description of the protocol and known codes can be found at http://www.boehmel.de/lanc.htm.

The protocol has 8 bytes. Bytes 0 & 1 are to control the camera while bytes 4-7 give the camera status. Control bytes have to be transmitted synchronously to arrive when Bytes 0+1 are expected. That's tricky from a programming point of view.

Fortunately you can buy a chip that does all the RS232 to Sony LANc conversion for you. This makes the programming part real easy. The chip is the ELM 624 (ELM624DS.pdf) and can be purchased from Canada for about £12 from here http://www.elmelectronics.com/index.html.

 

The ELM624 interface board

You have two choices, build your own or buy one from Underwater Minnesota

To build your own you will require the following:

ELM 624 1
LM7805 regulator 1
2N3906 transistor 1
100 NF capacitors 3
27pf capacitors 2
100 ohm 1
4,7 Kohm 1
10 Kohm 1
33 Kohm 1
100 Kohm 1
1N4148 diode 1
3.579545 Mhz Crystal 1
9 pin female COM port connector 1
2.5mm stereo jack plug 1
Cable  

 

ELM624 interface board Interface with connectors

 

The program

I used Visual Basic Express to develop the program and can make it available if contacted by email.

I wrote the program to interrogate the Sony HC7 camera codes. I have since rewritten it to be used with the latest cameras and to export SMI files which can be used to caption date and time code in media players.

The program has three forms. The first is to set up the program with known Sony LANc codes. The program searches for active COM Ports. You can use USB Serial adpters if your PC doesn't have one. There are six assignable text boxes where you can experiment with alternative codes. The set up form looks like this:

The second form is the control panel. The control features it has are as follows:

  • Power Off
  • Mode Switching: Camera / SD card / VTR
  • Time code and record time of day time and date reading
  • Camera status and raw status code received
  • Battery Low warning
  • Camera mode: Record, Record pause, Zoom, Auto / manual focus, write to the SD card, Photo capture, Backlight exposure,
    Assignable buttons 1-6.
  • VTR Mode: Play, Stop, Pause, Search rewind, Search forward, Fast rewind, Fast forward.
  • Menu navigation (only available on some cameras)
  • SAMI file export for synchronous captioning where the camera data is available on the lanc.

The final page is to fast step through lanc codes to test and discover what is available on a particular camera.


DONATION

You are more than welcome to copy of the program and use this information. Send me an email request.

If you would like to give a donation I would certainly appreciate it. All monies go to keep our diving club viable and pay for this web site.