User's Guide for the Ed-grip LANC controller


The LANC controller is mechanically based on a joystick, and the switch names 
in the source code reflect that heritage.  The joystick I selected (which I 
have lost all record of so I don't recall the manufacturer's name or model), 
has 8 switches that were laid out as:  trigger, hat switch (4 switches: up, 
down, left, right), left and right thumb buttons and a "pinky" switch.  The 
four switches that are currently laid out in a square were originally the four 
in the hat, so the names in the source are based on the hat and don't 
necessarily make a great deal of sense given the current square layout.

There are 4 indicator LEDs on the grip.  One is simply a power indicator, and is 
run right off the regulator.   The other three LEDS are used to indicate "sending 
command to camera", "shift button pressed" (the previously mentioned pinky 
switch) and "menu mode".   In the table below the shifted state is indicated by 
the prefix S:, menu mode is indicated by M:, and shifted state in menu mode is 
"M+S:"

"Menu Mode" is a feature where the grip has sent the code for the TRV-900 to 
enter its setup menu mode, and some of the switches have different functions to 
work in this mode.  The grip cannot tell what mode the camera is actually in, 
so menu mode should be entered and exited via the same method.  If the grip is 
used to enter menu mode, then the grip should be used to exit.  When the menus 
are entered via the grip, you should not exit the menu using the "Return" 
choice on the top level menu. The grip will still think that menu mode is 
active and the switches will not work the way you expect them to.
Likewise if the camera's "menu" button is used to enter the menus, then that
button (or the menu choice for Return) should be used to exit.  The grips 
switches will not be in menu mode when this method is used.


Switch Layout:

Thumb switches:


                Hat_Up     Hat_Right
       
        Left                         Right
                Hat_Down   Hat_Left



                  Trigger (front of grip)





        Shift (front of grip)



Switch functions:
All 4 Hat_* switches send codes continuously while they are held down.

Hat_Up
	M+S:	menu_up
	M:		menu_up
	S:		zoom_tele_fast
			zoom_tele_slow

Hat_Down
	M+S:	menu_down
	M:		menu_down
	S:		zoom_wide_fast
			zoom_wide_slow

Hat_Right
	M+S:	menu_select
	M:		menu_select
	S:		focus_far
			focus_far

Hat_Left
	M+S:	focus_near
	M:		focus_near
	S:		focus_near
			focus_near

Left 
	M+S:	no effect						
	M:		no effect						
	S:		toggle_backlight				
			fader							

Right
	M+S:	start_stop
	M:		no effect
	S:		start_stop
			toggle_display

Trigger:
	M+S:	toggle menu mode
	M:		capture
	S:		toggle menu mode
			capture (same as "photo button")


Engineering notes, a.k.a. things I learned while building this grip:

Biggest point was that silent switches are necessary.  The joystick I started 
with had the normal "clicky" button response you expect on a joystick.  On this 
device, this translates to hearing every button press on the tape.  I tried 
replacing the original switches with drop in replacements with much lower 
activation force, and while it did lessen the noise, it wasn't nearly enough.  
The current implementation has simple plastic buttoned momentary contact SPST 
switches I got at a local electronics surplus place.  

Ideally I think the best choice would be the molded rubber buttons like on TV 
remote controls.  They give enough feedback for you to know they've been 
pushed, and are essentially silent.  Another choice would be use reflective 
optocouplers which would have the advantage of being truly silent, but lack 
feedback and would most likely require some fancier programming to not draw too 
much power and to not be fooled by ambient light.

Mechanically, you should probably choose whatever layout works best for you.  
The grip I have isn't ideal since the joystick wasn't intended to be used as a 
support while the buttons are being pushed so you have to use a less than 
comfortable hand position.  All in all, it sure beats using the normal side 
strap and controls on the camera.

edc