Neon Chalk is a prototype piece of software designed to support drawing as play, for children with Autism Spectrum Disorders (ASD). It incorporates a minimalist interface to reduce distraction while drawing, compelling colours and sound that are configurable for each user, and an interaction design that makes the stimulus reward outputted by the software contingent on input from the child drawing. The design and development of the Neon Chalk prototype has motivated and informed the assessment of user-centred data gathering techniques. Six children with ASD were involved in this research. The techniques used within this study are evaluated based on their suitability of use with this challenging user population.