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Battery pack and switch box for Olympus T-28 macro flash unit

Once you have your flash bracket made, the next logical step of course  is to start using it.  One of the first things you will probably run into is that it can be hard to focus due to low light or because your lenses are slow.  The  Olympus T-28 twin  flash has modelling lights which are very useful under low light or when you are using the old Zuiko lenses on the new E digital bodies.  The battery pack for them are hard to find however, and the AC adapter is not very helpful in the field (and rather hard to find too).  So if you need to use the modelling lights, the simplest way is to make one yourself.  And while you are at it, why not make a switch box so you can turn the lights on and off  without using the rather inconvenient knobs on the flash heads?

Please note
Before I go any further guess this is necessary: I can not be held responsible for any injury caused to you or anyone trying to follow my guidelines, or for any damage caused to your equipment.  Also, all original ideas in this design are mine, you are free to copy this or modify for your own private use only - and if you find this helpful I would really love to hear from you.  Commercial reproduction based on my original design is not permitted.

Finding the material
Almost all you need is available from RadioShack (see list below)

The making
Pretty straight forward, simply soldering a few wires together and knowing how to connect a LED without accidently frying it.  See the pictures below.

  project box (3x2x1"; RadioShack #270-1801)
  2 x 5mm green LEDs (2.1V, 25mA, 6.3mcd; RadioShack #276-022)
  2 x 220 Ohm resistors for the LEDs (RadioShack #271-1111)
  1 x 1/8" mono plug (male; RadioShack #274-286)
  2 x 1/8" mono plug (female; RadioShack #274-333)
  2 x slide switch (RadioShack #275-409)
    machine screws and nuts for the slide switches (RadioShack #64-3010 & #64-3017)
  toggle switch (RadioShack #275-624)
Battery pack:
  D battery holder (RadioShack #270-396)
  2 x 1/8" mono plug (male; RadioShack #274-286)
  LowePro SlipLock Pouch 10 (fits the battery pack perfectly)
  two stranded wire (hardware stores, I used about 9')
  2 x coaxial power plugs (size "M"; RadioShack #274-1569)
  3 x 1/8" mono plug (male; RadioShack #274-286)
  1 x 1/8" mono plug (female; RadioShack #274-333) 

soldering iron, solder, something to make the holes in the project box, screwdrivers and other common tools.

I am not sure what the whole thing did cost me.  Lot of this is not necessary, like the pouch or the connectors, you can simply solder the wires to the switches.

The battery pack, pouch and switch box.
The swithch box has three switches.  Two small slide switches on top which allow you to control if the modelling lights on one or both flash heads are used.  The switch on the side is a "master" that cuts off the battery power to the slide switches.  There are also two green LEDs showing you if the corresponding circuit is closed or open.  

The whole thing in action - it works remarkably well.

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