Mum has been given a strange small beanbag like thing to keep her mobile phone in and find it easily.  Given that it is bright orange and now sat by the TV provided she remembers to put the phone in it this may work very well. It is made of fabric but I'm sure with a little application she should be able to come up with a pattern for knitting one.  I suspect it would need to be knit on small needles to ensure a close knit fabric.