The participants do not like manuals. 

When absolutely necessary, then they will read.

Most of the time, they will look up the manual or instructions on Youtube.

For pressing buttons, they should be tactile, and have some colour. This way thet are easier to detect.

A 'Beeldschermloep' has a little panel of buttons  and is a very useful product for visually impaired people   

Clear signals are necessary.

• There should be a difference between walking and cycling mode. 

• Keeping signals to a minimum.