Magic Selfie Mirror Infra Red Issue - Please Help!

[MMScreen]

Hi all,

I have a really bizarre issue with my Infra Red for my Magic Selfie Mirror. When an adult with very large fingers uses the touch screen to write their name, it usually works fine, however when someone with smaller fingers or children use it, the text comes it all in dots and doesn’t work very well at all. It is definitely to do with the size of the finger used as when I use my thumb which is much larger, it works perfectly, so it is a surface area issue but not sure why infra red would not pick up a small object?
I tested the infra red and there are no black spots or breaks.
Can anyone help?
Thank you very much in advance for any help.
Martin.