i am currently doing research for the new product development of barber chair for children or babies,is there anyone who would kindly enough to give me some advice or some info about that? 
one consideration you may need to note is that the chair for the kids gotta be designed with the barber (adult) in mind…
Have you watched children get their hair cut? What did you see? What happens when they arrive, and when they leave? What causes success and what causes failure? What do the parents say they hope for or are disappointed by in the process? What do the barbers like or fear about cutting children’s hair? Do they only cut children’s hair as a speciality or do they vary it throughout their workday? What kind of tools and products do they use that are different or do they use in a different way when cutting children’s hair? What are the key developmental stages that impact how the hair is cut (i.e., able to sit up, able to talk)?
I saw a barber who had chairs specifically for kids in the shapes of rocket ships, boats etc. Thought it was clever.
I think distraction is the name of the game with kids (that said, eliminating the mirror is probably a good idea!)