问题
I am wondering if this is even possible. I want to make my own software to control the release of the shutter via the remote shutter release. From the diagrams I have seen it has a 3.3 v (no load) and a threshold voltage of 1.8v. I am wondering if I can use limit a usb cables voltage which is around 5.25v, if I am understanding correctly. Is this even possible, or do I need to look in a new direction. I am hoping to write the software in c# which I am fairly confident in.
Thank you in advance for your help :)
回答1:
I've played a lot with these type of shutter remotes, for both the sony alpha and for the canon line of dslr's. For the cannon, it is usually a 2.5mm stereo plug. It has 3 contacts: ground, focus and shutter. Shorting each one of them and you will trigger that function in the camera.
http://www.doc-diy.net/photo/eos_wired_remote/
A few years ago, I designed my own circuitry that would take serial commands from the host (in my case an HP Pocket PC) and drive one of the lines down using a microcontroller GPIO port.
Nowadays there are similar devices with much easier connection and control options. And if you'd like to take the DIY road, there are very nice options such as the arduinos or if you're a c# addict, there are the netduinos.
Here's a commercially available solution, including SDK: http://www.breezesys.com/DSLRRemotePro/features.htm
回答2:
Working with USB devices in .Net is not the most straightforward task... There are no libraries in the BCL to deal with USB. However, it is possible to use Win32 API's.
This article should get you started in the right direction, as far as accessing a USB device if you want to pursue this.
As for whether it's possible, it might be... I don't rule anything out, but I think you're in for a LOT of research time to make it work if it's possible at all. (I've never seen anything in the Win32 API documentation that allows you to control the voltage, for example). However, it would be very cool if you could make it work, and the satisfaction factor alone may be worth the try.
Added
I took a look at PInvoke.net (a very good site for learning about Win32 API calls) to see if they cover power management for USB drives, and I see nothing at all.
http://www.pinvoke.net/search.aspx?search=usb&namespace=[All]#
来源：https://stackoverflow.com/questions/3409922/creating-a-usb-time-lapse-for-cannon-eos-rebel-xs-using-a-c-sharp-program