bool GetbBabyHasMoved()
{
return false;
}
Ah! and remember to glue the baby to the bed...
Now seriously:
it all depends on the kind of exercise they've given you... Which is the minimum movement you need to detect?
Using a web cam and comparing images could help...
Putting a sensor to the baby could help...
Using a cell phone with some api to find it's place could help...
...
Be more specific with your question please...