I'm not familiar with the sleep options so I can't help. The article by Nick Gammon that you linked to (and which I bookmarked) seemed comprehensive.
This thing will only be on when the user is using it so I wonder how important sleep mode really is. It's not the same as somethng that must be available 24/7.
Have you considered reducing the clock speed - perhaps to 1MHz?
...R
Robin2:
I'm not familiar with the sleep options so I can't help. The article by Nick Gammon that you linked to (and which I bookmarked) seemed comprehensive.This thing will only be on when the user is using it so I wonder how important sleep mode really is. It's not the same as somethng that must be available 24/7.
Have you considered reducing the clock speed - perhaps to 1MHz?
...R
I read Nick Gammons page and it was very helpful. As I said above 2ma over 5 seconds isn't much, however, the extra 2ma over several hours will add up, so I sleep in between timeouts and interrupts. So the basic idea is...
I am also already running at 1Mhz.
The latest version of the code is working really well on the bench, so it's time to build the prototype and test it in the real world. I just need to order a few parts, and then design and mill the PCB.
Regards,
Les
I am glad to say that I finally got a prototype up and running, so a big thanks for all the help and advice.
I made a major boo boo with my original design, as I didn't check the specs of the LM567, which is supposed to work at a minimum of 4.7v. 
Although it worked at 4.5v for me, a slight drop in the batteries would have rendered the device useless. Fortunately they do a low voltage version that works from 2-9v and I just had to change a few component vales, as the oscillator has to run at twice the frequency you wish to decode.
Battery life should be good as it's using about 1.5ma in standby mode, according to an online calculator this would give over 450 hours.
Regards,
Les
