Cord for 2 flashes - 7 d

I have both the OC 2 and 3 cords , but neither will allow 2 flashes . What I want to do is fire 2 flashes at same time , but no line of sight .
I want a cord that I can connect another cord to .
Thinking about 2 flashes , I already have a 380 and a 580 II and want to fire at same time .
What I am trying to do is make a time lapse and want to keep light the same for day and night . One shot an hour over at least 3 days to maybe a week .
I posted for a formula to figure out what setting with ND 3 BUT right person has not seen it
I will check the macro forum also .

What are you photographing that you don't have line of sight but can reach with cords? Another option is an inexpensive ($25) radio trigger.

I want to do a time lapse of flower opening . One flash pointed at flower [Bud to start] and the other to high light the leaves / plant . Several have budded / bloomed [white , yellow , frosted pink] but the double orange has not started a bud yet [Oh , this is for the brugmansia plant / angels trumpet] The flower should be about 14 to 16 inches long and probably 6 to 8 inches wide . If I can not figure out anything else , I will put in corner and use the 2 always on LEDS and hope .

Right now -5-23-12
Camera and flash in manual on Bogen tripod – may have to use gimbal head from Benro tripod , may use ring light instead of flash -it is alway on - will it reach 5 to 6 feet ?
Camera at 5 to 6 feet from plant
I have to figure out if constant light on bud will look funny at night with no sun light - - maybe the lamp idea or leds ?

Lens = 10-22 – set around 14 mm for DOF at 5 to 6 feet - at 5 feet away - tripod to flower bud .
An F 4 OR 5.6 do test shots for DOF - F 8 can cause flickering
Looks like a speed of 1/30 , one shot every hour
May need an ND filter to compensate for sun during day – do a few test shots if no answer to posed question
Shoot large JPEG - and RAW - I have a 16 GB , and 32 gb - should be big enough - [raw = May want one or 2 single shots later - just take longer to batch] cropping probably needed with the 10-22 at 14 mm
Since I want to do an angels trumpet [Brugmansia] and flower hangs down - the flash should be under camera - pointed up – shadows or the / ring light under bud ?

http://4.bp.blogspot.c​om …lashMonopodDual​Mounts.jpg

dual ettl cable

http://michaelbass.blo​gspot.com/

Thanks , I book marked site . Not of it made much sense to me . Maybe if I knew more - ? None of the items say - this will make 2 flashes fire at same time . All he says is add $ money for this or that but does not say what it does when added .
I was 1/2 way thru before I figured out DED meant dedicated .
Guess I need a book besides the 580 manual .
Now to find a good flash book

You can buy the Phottix Duo cord to set off 2 flashes at the same time. Here's where it gets tricky. Most people that use these cords use identical flashes and split the power. ETTL may not work correctly with 2 different flashes on the same cable. This would be ideal if you can set the power of the flashes manually. Unfortunately, the 380ex has no manual controls. You might be able to get this working with enough spacing and testing. Perhaps you can make the 380ex the main and dial down the 580exII in manual.

Have you thought about just getting a PC cable to connect the 580exII to the 7D? Then the 380ex could connect with one of the off camera cords that you already have. The other problem I just thought about is the 380ex going to sleep.

Thanks , I was just looking for a good flash book when I got the email . Did not find any on amazon that had ETTL in search .
I will go check out the Phottix Duo cord now .
edited
I bookmarked it , Tomorrow is a holiday
Checked out last night . Looks like it might work - today is holiday , but maybe store is open - Yes , I am one of the few who check out on net , then buy at my local store if they have it . I am a touch-e feely guy and if don't work / it's me or what ever - I take back . OK show me what I am doing wrong that you did not tell me when I bought it .
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I will also check for a good flash book there . I have 2 Peterson's books [UNDERSTANDING FASH and UNDERSTANDING SHUTTER SPEED] and he has one on flash - but it looks like it is like other 2 I have - mainly film .
I want one that covers ETTL [good / well - not just a mention] , LED lights and hopefully the intravalometer . Maybe the store can recommend one .

Where I am right now -
2 daylight florescence bulbs on all the time . The new battery for the quantum flash came in - won't be needing now - and the DC coupler for the 7D came in also .
Now , it is one shot every hour and is only good for 4 days at 32 gb but taking a shot every hour should give me time to remove card - slap in a 16 gb and download the 32 gb . Then swap back the 32 gb .
I would like to do from bud forming to flower shriveling , Beginning to look like at least 10 days - maybe more .
No buds forming yet - on 12 plants small enough the wife won't get upset about being in house .
It is unreal how much I have learned about the lighting , DOF , the 10-22 , 17-55 and the 180 macro