After some initial success with the range extender, the first attempt at a prototype was a failure. It just did not want to work and the pulses ending up at the IR LED were not so good.
After looking at the filtered pulse output of the smarty trigger on the scope again, the nice pulses looked like they’d be nice for the range extender as well. And there was still room on the little prototype board…
So, the extra two resistors, transistor and jack were quickly enough added to the original Smarty Trigger prototype. Testing was a grand success, too: the remote CLS flash triggered very nicely through a 25 foot stereo cable with 3.5mm plugs on the end.
I have redrawn the combined schematic below, adding the component values:
I have decided to standardize on using 2.5mm jacks and cables for triggering the dumb strobes and to use 3.5mm jacks and cables for driving the remote IR LEDs to extend CLS range. These cables are relatively inexpensive and can be obtained in pre-made lengths of 1, 3, 6, 10, and 25 feet. Double female adapters can be used to make even longer runs than single cables alone.
Here is a shot of it in action. Neither flash would fire without the prototype turned on (the sensor on the SB600 was completely covered with gaffer’s tape over the IR LED and the SB26 had the slave function turned off). The right angle connector goes to the IR LED taped to the SB600 through 25 feet of cable. The cable in the center goes to the PC connector on the SB26. A three AG10 button cell pack wrapped in tape and held by the the makeshift battery holder (aka cheap plastic spring clamp) powers the prototype. Current draw with the bench supply was under 1mA average, so given that these cells have a capacity of 70mA-hr, they should last for a while. AAAs would last for a very long time but add weight and bulk.
What remains is boxing it up nicely and adding on a distribution system for triggering high voltage strobes and additional remote CLS trigger IR LEDs… I am thinking of putting it into a shallow plastic electrical box for a single light switch. It is probably way bigger than it needs to be but I want at least 4 low voltage and 4 high voltage dumb slave jacks and another three CLS extender jacks.