Here is some Applescript code to go with grgarside's Answer
I tested and it works. The code needs to be saved as a stay open Application.
When the app is running it will try press the right arrow right. In this code I have set it to ten seconds
return 10 But depending on the length of time you set this could be a little bit of a pain if you switch out of aperture for some reason or want to quit the app.
So I have included a CAPS lock key down detection. Which will quit the App on the next iteration. You don't have to use it but it is there if you need to.
if isShiftKeyPressed() then
-- IF CAPS LOCK IS DOWN THE APP WILL QUIT
display notification with title "Arrow Right App" subtitle "quiting right Arrow App"
tell application "System Events"
tell application process "Aparture"
key code 124
return (do shell script "/usr/bin/python -c 'import Cocoa; print Cocoa.NSEvent.modifierFlags() & Cocoa. NSAlphaShiftKeyMask > 1'") is "True"
I have tested this in Aperture and it worked as grgarside suggested.
Remember to change the line
tell application process "Aparture" to you application if it is not Aperture.