I would happily just use the countdown intervalometer if I could turn off the screen between shots. This is possible in the Eco mode. Can I run the Eco mode and a script at the same time or does the Script override other controls?
I answered this in the other post you created.
Thanks no such directory in my SD card. Only a blank scripts folder.That's weird. It looks like you do not have all the files from the distribution folder copied to your SD card.
How did you setup your SD card? You appear to be missing critical files and folders. While a CHDK BASIC program may run with files missing, other strange things can happen. Not good if you plan to try and keep your camera running for weeks on end.
Just copying files to your SD card is not enough. I'd suggest you use the STICK
utility. Or one of the other installation methods described here : Prepare your SD Card
I can load and run the countdown intervalometer no problems (works great) - but I want to put the device in the field for 6 months and to do this I need to be able to turn the screen off to save battery.
The ultimate intervalometer was specifically designed to run for weeks at a time and does many "tricks" to make that happen more or less reliably. It has been tested many time and shown to run for months when configured correctly. More simple intervalometers will mostly not do this for you and have not been reported to run that long. You will want a lot more than just turning off the backlight, which does not actually save as much power as you might think.EDIT :
if you are interested in how long your battery will last, you might find this tread interesting : Battery Intervalometer