New to this forum and a novice with electronics, so pardon me if this is a really silly question. As one of my early projects, I want to use an Arduino Uno to trigger the shutter of my Canon camera. Canon professional cameras, as you may know, use a shutter release cable comprising three leads: two hot ones for focus and the actual shutter release with the third being for ground. I'm only concerned with the one for shutter release. Short it to ground and the camera fires. So, how to do this with the Arduino? I've seen others use optoisolators to keep the camera's shutter release circuity completely independent of system current. Can I use a simple transistor instead? Is there a real risk of connecting the camera's shutter release circuity to the common ground?
Apologies if I haven't explained this correctly.
You can use either two (or one), transistors (with base resistors) , optoisolators (with LED input current limiting resistors), or even small 5 vdc relays to perform the functions. Circuit isolation is not required in this application but many like to do it anyway.
I'm a fan of using small reed relays for such functions but people call me an old foggy, but that way I don't have to think too much about what the camera's contact operating voltage is, what the polarity of the contact interface is or how much contact current is being switched when activated, I'm just wiring 'dry contacts' to the camera. Here is one that can be directly wired to an arduino output pin, (but do wire a reversed diode across the relay coil terminals for transient protection) as it only draws 10 millamps from the output pin to operate, plus you gain total electrical isolation between the arduino and the camera.http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_1860070_-1