Newsgroups: comp.robotics
From: bigwoodp@kbcomms.demon.co.uk (Paul Bigwood)
Path: cantaloupe.srv.cs.cmu.edu!nntp.club.cc.cmu.edu!hudson.lm.com!netline-fddi.jpl.nasa.gov!elroy.jpl.nasa.gov!swrinde!pipex!demon!kbcomms.demon.co.uk!bigwoodp
Subject: Re: Remote controls for JVC GRAX70 video camera
Distribution: world
References: <3d2ud3INNsu3@RA.DEPT.CS.YALE.EDU>
Organization: Karibu Communications,Thatcham,Berks
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Date: Tue, 3 Jan 1995 14:46:09 +0000
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In article <3d2ud3INNsu3@RA.DEPT.CS.YALE.EDU>
           griest-tom@cs.yale.edu "Tom Griest" writes:

> Does anyone know the interface for either the wired or IR remote controls
> on the JVC GRAX70 video cam-corder (or a contact at JVC that could provide
> it)?  We want to be able to control it (especially the zoom) from a computer.

Tom,

I'd also be interested in any info on the protocol used by JVC for their
IR control. I've tried to obtain the requisite info from JVC here in the UK
with no success. I've got a GRAX60 camcorder and have found that my VCR is not
compatible with the codes used by the IR controller.

I found out by trial and error that code 90 (not listed in the manual)
would switch my VCR on, and could control the VCR basic functions (PLAY,REW,FF
STOP,REC etc) but it wouldn't stop and start the VCR using REC/PAUSE when doing
an assemble edit sequence. 

Playing with another VCR that was listed, I discovered that the problem appears 
to be related to how the REC/PAUSE function was implemented on my VCR. On mine 
pressing PAUSE whilst in REC mode would enter REC/PAUSE OK, but to restart the 
recording needed the REC button to be pressed. The other VCR just needed the 
PAUSE button to be pressed again to restart recording.

So it would seem that the JVC remote control function of the Recording VCR is 
simply a switch that activates the pause function either directly using the 
wired remote pause function or controls the IR remote to transmit the Pause 
function code for the appopriate VCR as programmed in the setup of the IR 
remote. 

A VCR servicing book I have indicates that most Camcorders Remote Edit
socket is simply a power FET controlled by the camcorder. This seems to back
up the above.

I am now thinking along the lines of designing and building some form of 
IR controller box that could learn the two codes and play the appopriate one 
as required on command from the Camcorder.  I recall that sometime last year 
(1994) I read something in one of the newsgroups about a simple adaptor that 
could be plugged into a serial port of a PC and could read the bit pattern
into RAM from an IR control. I think it was related to the control L 
protocol, but since it included C source, I'm sure it could be modified.

Any pointers would be appreciated since I've definately lost the original 
source pointer.

73s de Paul

-- 
Paul Bigwood G3WYW                              Karibu Communications,
Tel/FAX: (44) (0) 1635 861981                   18 The Martins, Kennet Lea,
E-Mail : bigwoodp@kbcomms.demon.co.uk           Thatcham, Berkshire RG13 4FD
Specialists in Mobile Communications, - Voice & Data using Radio and Wire
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