Wednesday, April 29, 2020

Experiments with LANC on my Sony GV-S50 Video Walkman

An Arduino Uno with a LANC interface on a horrible looking shield.

I've been working from home, and I've of course been playing stuff while I work from my LaserDisc player, and 8mm Video Walkman GV-S50 playing some stuff I recorded in the 90s... MTV AMP and a few hours of a local WRUR electronica/trance show called "Digitalis".

Sony Video Walkman GV-S50

But of course, since I've got the deck right here next to me, and it doesn't have an IR receiver or any way to remote control it, I need to solve this major problem. ;D

LANC port is the 2.5mm jack on the bottom labelled "REMOTE"

The deck has a LANC connector on the back, and I happened to find a 2.5mm plug the other day, so this seemed like an obvious thing to do.  Obviously.

The schematic I based my circuit on. I did not include the 'push rec' button,
and I added a switch between LANC +5 and this circuit so I can decouple the power.
The transistor diagram shows the view of the transistor looking at the bottom of the device.

I found this schematic to interface to the LANC port, along with this arduino sketch that lets you just send the two byte commands out from a serial interface.   Thanks to getting totally confused from the article I found, I re-read through this doc about the LANC commands and figured out that what I need to do is send the standard command byte (0x18) followed by a standard command, and the deck will do what i command it to do!  So I did have it working, and better yet, the deck provides enough current to power the Arduino directly from the port.

My very slightly tweaked circuit

I made a tweak to the circuit just so that I could not worry about the 5V from my computer mingling with the 1990s 5v coming out of the VCR, so I added a switch.  In the pic of the shield above, the blue pushbutton switch can be seen by the second usb port.  That board has been re-used for a few projects, so there's only a couple of components on there that are actually for this one.

The only things on this board that are for this project are the blue switch in the bottom left, the transistor and zener diode in the middle and 4 of the resistors.  The schematic only shows two, but I didn't have a 5.6kΩ resistor so I cobbled one together using three in series.

The docs there weren't complete for this deck (Sony Video Walkman GV-S50), and I found a few more commands (volume, megabass) so I thought I'd put the list of commands here for future reference:

Group: (0001 1000) (0x18) - Normal Command to VTR or Video Camera 

  • 1830  stop
  • 1836  rew
  • 1838  ffwd
  • 1834  play
  • 1832    pause (still)
  • 1840    still
  • 1860    frame reverse
  • 1862    frame forward
  • 1850  search - (scan until 'play' or 'pause')
  • 1852  search + (scan until 'play' or 'pause')
  • 185E  power off
  • 18b4  counter display/data screen
  • 188c  counter reset
  • 18b0  tape speed (LP/SP)
  • 183a  rec  (untested, assumed to work)
  • 183c  rec-pause (untested, assumed to work)
  • 18d0  audio dub? (untested, might work?)
These were not listed on the LANC page, but I poked around until I found them:

  • 1876  megabass toggle *
  • 1824  volume +
  • 1826  volume -
  • 18fc  still/shuttle (still frame)
  • 1846  slow
  • 184c  x9 speed (scan forward)

Group: (0001 1110) (0x1e) - Normal command to still video camera)

  • 1e52  photo preview (scan forward)
  • 1e5e  power off

I tried a lot of the commands with the TV Tuner card installed, and none that I tried seemed to control it at all. (channel up/down, timer functions, menu functions).  In general, none of the menu interaction commands worked at all, sadly, other that direct tape speed, counter reset, megabass mentioned above.

I eventually want to have an IR Receiver module on there, and program it to receive commands from my mega sony remote, but for now, i can type the commands out to the serial port. For example. if I type 1834[RETURN], it is the equivalent of pressing [PLAY] on the deck.

Reference Links: