bigshot electronic flash conversion
this is the prototype for a switch activated by the striker that breaks the tab on a magicube for detonation. i will leave this process and add the revision to correct flash/shutter sync
ready light and on/off switch. case is made from black acrylic.
flash head. set at same hight as a magicube only 1/4" forward.
for months, off and on, i struggled with this switch. made a few of them, but none would fire. prototypes were made of brass, spring contacts as in battery contacts from 600's film bay and the timed sequence contacts from the gear section of 600's.
there must have been some issue with impedence or other electronical mystery beyond my comprehension, because as soon as i eliminated the heavy metal, it worked. finally settled on carbon fiber with contacts made of solder. that was it
for the guts i chose a 110, a vivitar 600 to be exact, as the compact size of the camera ensured that i wasn't going to get a circuit board that was spread out all over the camera's interior, like some models.
i set the contacts primarily at the same distance that the hammer travels to strike the bar inside the magicube. to synchronize the flash, the switch can be raised or lowered, via shims, to advance or delay the flash. to determine the sync of the flash, in a dark room, i placed a mirror in front of the lens and with the film bay opened, looked down to the back of the shutter.
REVISION
flash shutter sync complete and working. in the process i found the vivitar 600 flash to be lacking. now using a minolta auto 25, which is sufficient, but on the lower end of needed brightness.
the striker travels upward about 5/16" to 3/8". the prototype ended up being at the furthest point that the striker could reach and found that it fired at the first half of shutter sequence. there was a need to delay the switch. not being brilliant in the electrical field and after consulting an e-wiz, i felt that a mechanical solution was my only option.
common magnesium flash bulbs burn for 1/30 of a sec. which is why the mechanical setup of the bigshot worked without a sophisticated sync mechanism. 1/30 sec. offered a wide window for shutter action.
the minolta fires from 1/40,000 to 1/2,000 of a sec.on auto, manual mode, set at 50 ft. brings it down to 1/2,000 sec.
my delay consisted of the introduction of weight to the original prototype. using a battery contact out of a 600 with solder for weight, it enabled the switch to be placed further away, with the weighted pivot half way of the distace to contacts. the striker now stikes the weighted tab, throwing it up to the now further distance of the contacts. it still can be adjusted to advance/delay flash. check it out.
acrylic base with carbon fiber tabs, solder contacts filed flat. isolated with rubber grommets
the small spoon shaped area of the pivot is filled with solder for weight.
the only light source is the flash, in a dark room. light/dark set for max light. need a bigger flash unit. as much as i hate to do it, i will cut off the original flash diffuser lens and housing to mount a cold shoe to secure the flash unit . also a cover for the switch is in order.
this is still a work in progress as i'm still trying to scrounge four 1.2V 800 mAh rechargable NiCad batteries for my monster Vivitar auto 281 flash unit.
ready light and on/off switch. case is made from black acrylic.
flash head. set at same hight as a magicube only 1/4" forward.
for months, off and on, i struggled with this switch. made a few of them, but none would fire. prototypes were made of brass, spring contacts as in battery contacts from 600's film bay and the timed sequence contacts from the gear section of 600's.
there must have been some issue with impedence or other electronical mystery beyond my comprehension, because as soon as i eliminated the heavy metal, it worked. finally settled on carbon fiber with contacts made of solder. that was it
for the guts i chose a 110, a vivitar 600 to be exact, as the compact size of the camera ensured that i wasn't going to get a circuit board that was spread out all over the camera's interior, like some models.
i set the contacts primarily at the same distance that the hammer travels to strike the bar inside the magicube. to synchronize the flash, the switch can be raised or lowered, via shims, to advance or delay the flash. to determine the sync of the flash, in a dark room, i placed a mirror in front of the lens and with the film bay opened, looked down to the back of the shutter.
REVISION
flash shutter sync complete and working. in the process i found the vivitar 600 flash to be lacking. now using a minolta auto 25, which is sufficient, but on the lower end of needed brightness.
the striker travels upward about 5/16" to 3/8". the prototype ended up being at the furthest point that the striker could reach and found that it fired at the first half of shutter sequence. there was a need to delay the switch. not being brilliant in the electrical field and after consulting an e-wiz, i felt that a mechanical solution was my only option.
common magnesium flash bulbs burn for 1/30 of a sec. which is why the mechanical setup of the bigshot worked without a sophisticated sync mechanism. 1/30 sec. offered a wide window for shutter action.
the minolta fires from 1/40,000 to 1/2,000 of a sec.on auto, manual mode, set at 50 ft. brings it down to 1/2,000 sec.
my delay consisted of the introduction of weight to the original prototype. using a battery contact out of a 600 with solder for weight, it enabled the switch to be placed further away, with the weighted pivot half way of the distace to contacts. the striker now stikes the weighted tab, throwing it up to the now further distance of the contacts. it still can be adjusted to advance/delay flash. check it out.
acrylic base with carbon fiber tabs, solder contacts filed flat. isolated with rubber grommets
the small spoon shaped area of the pivot is filled with solder for weight.
the only light source is the flash, in a dark room. light/dark set for max light. need a bigger flash unit. as much as i hate to do it, i will cut off the original flash diffuser lens and housing to mount a cold shoe to secure the flash unit . also a cover for the switch is in order.
this is still a work in progress as i'm still trying to scrounge four 1.2V 800 mAh rechargable NiCad batteries for my monster Vivitar auto 281 flash unit.