Hi,
That sounds like just the ticket! Do you have a copy of the circuit or a URL for such. Mentioning the 350D, I built a timer circuit using the venerable 555 chip so I could use long exposures on my own 350’s.
There’ll be a solution somewhere!
cheers,
Bill.
PS. It’s just occured to me I could probably do it with one of the Arduino’s I have, DOH!!!