Quest for the Whistler Button

Do yourself a favour and go watch that movie. There is a huge Hollywood sized grain of salt needed any time you deal with: Hacking, Computers, Internet, etc.. but this movie is EXCELLENT at showing 'Red Team' activities, social engineering, physical bypasses, and true historical hacking (debugging an IC to see what it does).

There is great comedy, action, and intrigue in this film and should be in the top 3 of any nerd movie list.

.. or bury a rpi-zero in it, and turn the thing into a battle station ..

Devices can have multiple users. A blind passenger in the rear seat can use a drive-through ATM.

People with "disabilities" often have to buy off the shelf equipment made for the mass population, and then adapt it for their needs since most products aren't designed with them in mind.

People who are blind don't necessarily lack vision - that's why the bobbled paving slabs at the edge of crossings and train platforms are bright yellow. [1] Admittedly the LED wouldn't do anything a tactile or audible click wouldn't do here, but a blind user most likely would be able to see that an LED was lit somewhere.

[1] https://www.youtube.com/watch?v=cdPymLgfXSY

aside from it being embossed tape added after market:

blind covers a lot of ground. the ability to discern a red led against a black background when you're a couple feet away is well within the realm of blind