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Hot-shoe signal to external GPS

Started Apr 24, 2017 | Questions thread
mawyatt2002
mawyatt2002 Contributing Member • Posts: 502
Re: Hot-shoe signal to external GPS

lidar532 wrote:

Hi there,

I've done this many times with Sony and Ricoh cameras, and you generally have to simply use a "Pull-up resistor". To implement, on the GPS Event input, simply connect a 10k resistor from the Event input to the 3.3 volt power bus. Connect the input to the hot shoe center contact, and a ground wire from the GPS ground to the hot shoe ground. When you actuate the shutter, the camera will usually generate a "low active" signal while the shutter is open. The GPS should easily accommodate any pulse width down to at least 1 micro second which is much shorter than any shutter setting you can generate. Be sure to configure the GPS even input for "high to low" transition detection. You should not need any debouncing circuit.

-Wayne

Hi Wayne,

Some of the new cameras have an electronic shutter mode that is used for the 1st and 2nd shutter, thus no mechanical shutter, and totally silent/vibration free. I found that the hot shoe "flash" trigger is disabled when in this mode with the Nikon D850, but believe other cameras also block the hot shoe trigger during this mode. The reason may be to prevent flash/strobe bleed thru when reading out the sensor (electronic shutters are not totally opaque).

Anyway, here's a link to a circuit solution I did using a 555 timer. Other software based solutions are available in macro stacking controllers.

https://www.photomacrography.net/forum/viewtopic.php?t=36356&postdays=0&postorder=asc&highlight=555+timer&start=15

BTW why not just trigger the GPS with the same signal that triggered the camera?

Best,

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