1.11 If using cards, ensure that the card can be inserted into the card reader in its correct orientation without requiring vision
Incorporate an embossed capital letter at least 10mm high with an embossing of at least 0.7mm. Note that, whilst Braille may seem a more obvious solution for tactile marking, less than 2% of visually impaired people can read Braille.
Incorporate an orientation notch on the card
A 2mm notch on the trailing edge of the card will enable the user to correctly orientate it for insertion into a horizontal slot by touch. This follows the CEN standard EN 1332 (Machine readable cards, related device interfaces and operations. Part 2 Dimension and location of tactile identifier for ID1 cards). Note that the slot should also be orientated in a way that fits the standard.
Allow the card to be inserted in any orientation
If possible, the card reader could be designed so that the card can be inserted or swiped in any direction and with either side uppermost or leftmost. This will remove the possibility of errors. It does not, however, mean that there is no need to add an orientation notch on the card, since users who do not realise that any orientation is acceptable will then be unsure of what to do.
Generate an audible error indication when the card is inserted in the wrong orientation
If the card is inserted in the wrong orientation, immediately reject it and notify the user of the error using an audible indicator such as a low beep which suggests failure. Then allow the user to try again.
Consider using contactless cards
Contactless cards work at a distance. They do not need to touch the reader device or to be placed in any particular orientation. The maximum working distance is typically no more than 10cm for security reasons. Other types of cards include those that must be pressed onto a pad but can be in any orientation.
Consult international standards
International standards relating to card systems include:
- CEN (Comite Europeen de Normalisation) EN 1332
- ISO (International Standards Organisation) 7816 & ISO/IEC 10536
How you could check for this:
Self-test early prototypes
Designers can run simple tests themselves on an early prototype, by simulating sightless use. This can be done either by wearing a blindfold, turning off the lights or putting cards in a black bag. If working blindfolded or in the dark, extreme care should be taken to avoid injury through loss of balance or collision with unseen objects. This may require that the test user remains seated or, if they have to move around, obstacles such as floor cabling are removed in advance.
Test with real users
During development, you should test the prototype in a realistic situation with real people who have complete visual impairment. In particular, you should include people who are recently impaired and have not yet developed enhanced tactile abilities.
About user testing