Neurodevelopmental Engineering is a new interdisciplinary research area at the intersection of developmental neuroscience and bioengineering, mainly concerned with quantitative analysis and modeling of human behavior during neuro-development. Along such a line, our research focuses on early diagnosis of neurodevelopmental disorders such as Autism, currently diagnosed after 3 years of age. We propose a novel approach to the assessment of basic patterns of goal-directed actions in normally developing babies, in the 0-24 months of age range, both under laboratory and naturalistic conditions. In particular we propose novel mechatronic devices, either wearable or embedded into toys, for ecological, unobtrusive assessment of infants behavior. Guidelines for the design of a particular toy embedding both kinematics and force sensing capabilities as well as of experimental scenarios where similar instrumented toys can be deployed are provided. Preliminary experimental data carried out in ecolo...