I went alarm clock too!
I found a clock online for kids with two sheep on it, one up walking in the daylinght and one asleep in bed at night. One half is illuminated at a time so you switch it on and the sheep asleep is illuminated. When the clock (on the back) reaches the time you set (7.30 in my house) the other half illuminates so the day sheep can be seen.

It took about 3 days for DD to work it out at age 2.2, I would say she can't get up until the sheep wakes up. Now she might wake early, but waits until the "sheep is awake". Brilliant!