Wont sleep longer than 30 minutes....

[Matryoshka]

Yes but for us it was breastfeeding, he was waking to breastfeed every 15 mins, 30 mins, 1 hour etc round the clock. It only lengthened at 6 months when i introduced solids, then he would go 2/3/4 hours. We just ended up co-sleeping out of necessity, which if you don't mind can be a wonderful experience, we are still doing it now. He can sleep in his own bed when he wants to, but at 20 months he still wakes up once/twice in the night so having him in our bed is more convenient for me.

Some babies are just frequent feeders/wakers. I found it got easier once i stopped trying to force him to go in the cot or sleep for longer - i also didn't like the advice from Ngala. It worked out best for us by myself just following his lead, luckily i stay at home with him so i have that luxury. It can be really hard to get stuff done around the house but that gets easier as they get older and want to get involved.

[bucca]

My 5 month old DD also sleeps only 1 sleep cycle during the day resulting in her only having 4 30-45 minute sleeps all day.. however unlike in your case she wakes up alert and very happy and doesnt need another sleep until a couple of hours later so she obviosly only needs this amount of sleep (in the nights she doesnt go to bed until 10pm but will sleep in until around 8:30am, even though shee feeds twice in that time).

While looking up on a few things to help her (from which i found out i needent bother) i found this link, hope it can help you, for more just Google 'sleep cycle', 'catnapping' and 'baby' or similar terms.

Solutions for catnapping and longer day sleeps - The Sleep Store, New Zealand