DIY Hot Shoe Electric Plug.
As electric plugs for a camera’s hot shoe are difficult to find (1), I have built three versions which can be used to trigger an external device.
Plug 1. The plug core is made of sheet metal from a food can, sanded with fine sand paper to remove the plastic coating. The side edges are folded to slide into the camera's hot shoe. A 10 mm center hole accesses the camera’s hot shoe center contact. The rear edge is bent up as a pull tab (Fig 1 & 2)
A small square of ABS plastic is glued to this plug, with a hole in its center for a small, oval head screw. Two thin insulated wires about 8 cm long are soldered one to the screw and the other to the pull tab (Figs 3 & 4).
I have used this plug to trigger a photo flash, and it has worked every time.
Plug 2. A black plastic hot shoe protector, like the one included with a new camera (or from eBay) is the main part of the plug. It has two contacts (Fig 5)
a) The first contact is through a 5 mm diam. hole, aligned with the camera’s central ground contact, to hold the coil spring from a ball point pen. A short length of electric wire is soldered to the spring, and a small drop of ABS glue secures it in place.
b) For the second contact, a 1 mm lengthwise slot is cut, front to back, along the top edge of the protector with a hacksaw, to make room for the lengthwise wire contact. The contact is made from wire is cut from a large (50 mm long) paper clip, and one of its ends, 5mm long, is bent sharply at a right angle.
Parallel to the front edge of the protector, a hole is drilled horizontally through the upper level of the protector to accept the bent end of this wire (Fig 6, not to scale).
The wire is laid in slot cut above, and the bent end of the wide is plugged into the drilled hole. The wire is secured to the slot with a small amount of ABS glue (Fig 5). The middle length of the wire is kept bare to connect with the camera’s hot shoe. A short length of insulated thin electric wire is soldered to the wire’s far end. This plug should fit snugly in the camera’s hot shoe. I tested the connections for continuity with an ohmmeter.
Plug 3) This plug is battery powered by a coin battery holder glued to its base with ABS cement. The battery’s positive is connected to a red wire (Fig 7).
The battery’s negative is connected through the coil spring to the camera’s hot shoe’s center contact; the hot shoe ground frame is connected to the shoe’s side contact wire, and to a white wire. The circuit is closed each time a picture is taken, to fire an LED strobe trigger, for example.
1. Reference: https://wetpixel.com/forums/index.php?/topic/66895-hot-shoe-plug-where-to-get-one/&tab=comments#comment-422528 .
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