Thursday, May 10, 2012

A simple mod to assist the visually impaired

Appliance remote controls usually have more than half a dozen keys. And generally they follow the 80/20 rule: 80% of the keys are used 20% of the time. For the blind, it's a nightmare scanning the keys with their fingers and inadvertently pressing the wrong ones, particularly buttons they're unfamiliar with because they don't need to use them.

For a particular remote control that my dad uses, only 2 keys out of the total of 9 are relevant to him. To prevent possible errors in operation, I opened up the plastic case and inserted a sheet of paper between the rubber keypad and the printed circuit board. The paper presents a barrier that's electrically nonconductive and prevents contact between the electrically conductive pads of the keys and their corresponding contacts on the pcb. I then cut out the two areas for the buttons that he will be using.

Thus, when either of the two keys are pressed, no paper blocks the buttons from making contact with the circuit board, allowing normal operation. On the other hand, pressing any of the other keys, however hard you may do so, will not cause the remote control to send any infrared signal to the appliance because the paper prevents electrical contact.

If in the future other keys will need to be "unblocked" it's a simple matter of cutting out the relevant portions of the paper insert.

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