DSLR Shutter - through a USB port

[erick]

I've been successfully using DSLR Shutter to drive my Pentax K100D shutter through the parallel port of my old lappie. I finally put a small relay into the cable to operate the shutter by having the pin voltage change at one of the parallel port pins driving the relay coil and closing/opening a set of contacts.

Now I want to move DSLR shutter to my new little el-cheapo Acer, but no more parallel ports, nor serial ports, just USB 2.0.

I want the cheap solution. (Shoestring DSUSB??? huh? Keyspan connectors - Huh? Sounds like spending money to me.)

I can spend time researching or just ask here and see if anyone takes pity on me and advises :D

So, to my uneducated brain, the way I see it is that I must be able to make DSLR Shutter talk to one of the USB ports - true? If so, I must be able to get one of the pins going up and down as DSLR Shutter does its stuff - true? If so, I should be able to take that signal to my little relay's coils and I'm up and running!

Grateful for anyone to set me straight here.

Thanks
Eric :)

[Screwdriverone]

Hi Eric,

Sounds like that if you are using the electrical signals of the parallel port to drive a relay via the DSLR shutter program, then wouldnt a USB to parallel converter work just as well? I may be off base but the theory is sound?

Cheers

Chris

[mswhin63]

USB to parrallel converter would be great but if the application is DOS based and need to operate through windows then you may have some problems. The driver for the USB to parrallel convertor tie up the parallel port continually and the port may not be available to use for DOS based program.

Bartel's is know to have this problem. Bojan might be able to answer that better.

If it is a windows based program then Should be OK.

[erick]

If I can just find the right signal at a USB pin, then I'll be fine. I won't need the USB to parallel converter. (I would make up a connecting lead because I want to hold open the option of driving the camera from a computer with a parallel port still.)

But I suspect I don't understand how USB works. I'm from the olden days of parallel and serial ports which seemed to each have to be dedicated/specified - LPT1:, LPT2:, COM1: etc. Eg. I don't understand how one just plugs hubs and keyboards and things into one USB port and suddenly you have lots of USB ports!? Is it all to do with new-fangled modern intelligence - the software works out by itself where on all the USB ports to find the device it has to talk to - something to do with plug 'n play? Bring back the 5.25" floppy, that's what I say! And I had colour screens - you had a choice of green or orange!

[kustard]

USB is a high speed serial protocol. It uses lots of handshaking between the device and the host to determine what the device is. I'm actually currently working on a USB embedded project for work and it's not a simple system, it has a lot going on.

If you got yourself a USB to serial port converter you could write a program in say VB to toggle the RTS which you could stick onto your relay.

Or if you are more adventurous then you could program up an Arduino or similar to receive RS232 and toggle any number of I/O.

[erick]

I should say more about DSLR Shutter. It is a Windows program as far as I understand (attached)

I've attached the options it gives for ports to connect to the camera. I successfully use "0x3BC-LPTx" for the parallel port on my old lappie.

From the message at the top, it looks like it is sad to not find a ShoeString DSUSB device attached. But that will cost me money. If I'm going to spend money, I'll just spend the $50 or so to buy an interval timer for my camera from Hong Kong.

So can I select one of the others, then go to a (particular) USB port and find a pin going up and down with the software operation? I suspect life is not that easy with USB. :sadeyes:

[erick]

I did buy one and gave it to my son, the computer science graduate. He got his PC talking to it, but didn't go further. I was looking at a flash-triggered circuit to catch lightning on the DSLR! I must give him a nudge.

[kustard]

Having a look at those piccies then I get the feeling that a USB to Parallel converter MAY work. But it may also not as it could be more hardware reliant and USB converters often don't facilitate hardware driving like on-board hardware does,

I'd definitely poke your son :D
You could easily have it receive a character from the computer and toggle an output, you'd only need a terminal program to do it too.

[Marke]

Dont know if this is any good to you but its what I use

http://www.store.shoestringastronomy.com/products.htm

[erick]

Looking like I should just buy an interval timer. Several different makes - about AUD44 from Hong Kong. Thanks all. :)

[erick]

Shoestring USB Shutter Control - $105 from Bintel and I need to make up a further lead to the camera :sadeyes:

[Marke]

yes I know I got it direct from Shoestring including cable - worked out cheaper.